Camel case and snake case
(Redirected from Camel Case and Snake Case)
You are encouraged to solve this task according to the task description, using any language you may know.
Two common conventions for naming of computer program variables are Snake Case and Camel Case.
Snake case variables are generally all lower case, with an underscore between words in the variable, as in snake_case_variable'. Camel case variables are generally lower case first (except in some Pascal conventions or with class names in many other languages), with captalization of the initial letter of the words within the variable, as in 'camelCaseVariable'.
Leading underscores are not used in such variables except as part of a different naming convention, usually for special internal or system variables. White space is not permitted as part of camel case or snake case variable names.
- Task
- Write two functions, one to change snake case to camel case and one to change camel case to snake case. If possible, generalize the function enough to apply to strings containing spaces between words or a `-` dash between words, assuming that in those cases a space or hyphen is a also a separator character, like `_`, for the purpose of creating a new variable name. Leading or trailing whitespace may be ignored.
- Show the results on changing to both snake case and camel case for each of the following strings:
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
- Related tasks
11l
F snakeToCamelCase(nam, sep = ‘[_]+’, lcmiddle = 0B)
‘ convert snake '_' separator case to camel case ’
I nam == ‘’
R nam
V words = nam.trim(‘ ’).split(re:(sep))
I lcmiddle
words = words.map(w -> w.lowercase())
words = [words[0]] [+] words[1..].filter(w -> w.len > 0).map(w -> w[0].uppercase()‘’w[1..])
R words.join(‘’)
[(String, (String -> String))] funcs
funcs [+]= (‘snakeToCamelCase’, nam -> snakeToCamelCase(nam))
funcs [+]= (‘spaceToCamelCase’, nam -> snakeToCamelCase(nam, sep' ‘\s+’))
funcs [+]= (‘kebabToCamelCase’, nam -> snakeToCamelCase(nam, sep' ‘[\-]+’))
funcs [+]= (‘periodToCamelCase’, nam -> snakeToCamelCase(nam, sep' ‘[\.]+’))
funcs [+]= (‘allsepToCamelCase’, nam -> snakeToCamelCase(nam, sep' ‘[ \-_\.]+’))
funcs [+]= (‘lowermiddle_allsepToCamelCase’, nam -> snakeToCamelCase(nam, sep' ‘[ \-_\.]+’, lcmiddle' 1B))
F camel_to_snake_case(=nam, allsep = ‘[_]+’, sep = ‘_’, lcmiddle = 1B)
‘ convert camel case to snake case (separate with '_') ’
nam = nam.trim((‘ ’, "\t", "\r", "\n")).replace(re:‘([A-Z]+)’, sep‘$1’)
V sep1 = I sep == ‘.’ {‘\’sep} E sep
I lcmiddle
nam = (nam.split(sep1).filter(w -> w.len > 0).map(w -> w.lowercase())).join(sep)
E
nam = (nam.split(sep1).filter(w -> w.len > 0).map(w -> w[0].lowercase()‘’w[1..])).join(sep)
R nam.replace(re:(allsep), sep)
funcs [+]= (‘camel_to_snake_case’, nam -> camel_to_snake_case(nam))
funcs [+]= (‘preserve_midcaps_camel_to_snake_case’, nam -> camel_to_snake_case(nam, lcmiddle' 0B))
funcs [+]= (‘allsep_to_snake_case’, nam -> camel_to_snake_case(nam, allsep' ‘[ \-\._]+’))
funcs [+]= (‘allsep_to_kebab_case’, nam -> camel_to_snake_case(nam, allsep' ‘[ \-\._]+’, sep' ‘-’))
funcs [+]= (‘allsep_to_space_case’, nam -> camel_to_snake_case(nam, allsep' ‘[ \-\._]+’, sep' ‘ ’))
funcs [+]= (‘allsep_to_period_case’, nam -> camel_to_snake_case(nam, allsep' ‘[ \-\._]+’, sep' ‘.’))
funcs [+]= (‘allsep_to_slash_case’, nam -> camel_to_snake_case(nam, allsep' ‘[ \-\._]+’, sep' ‘/’))
L(f_name, f) funcs
print(‘Testing function ’f_name‘:’)
L(teststring) [
‘snakeCase’,
‘snake_case’,
‘snake-case’,
‘snake case’,
‘snake CASE’,
‘snake.case’,
‘variable_10_case’,
‘variable10Case’,
‘ergo rE tHis’,
‘hurry-up-joe!’,
‘c://my-docs/happy_Flag-Day/12.doc’,
‘ spaces ’]
print(teststring.rjust(36)‘ => ’f(teststring))
print()- Output:
Testing function snakeToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable10Case
variable10Case => variable10Case
ergo rE tHis => ergo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
Testing function spaceToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ergo rE tHis => ergoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
Testing function kebabToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snakeCase
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ergo rE tHis => ergo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
Testing function periodToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snakeCase
variable_10_case => variable_10_case
variable10Case => variable10Case
ergo rE tHis => ergo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12Doc
spaces => spaces
Testing function allsepToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ergo rE tHis => ergoRETHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function lowermiddle_allsepToCamelCase:
snakeCase => snakecase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCase
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10case
ergo rE tHis => ergoReThis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _case
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ergo rE tHis => ergo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function preserve_midcaps_camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _cASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ergo rE tHis => ergo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function allsep_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake_case
snake case => snake_case
snake CASE => snake_case
snake.case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10_case
ergo rE tHis => ergo_r_e_t_his
hurry-up-joe! => hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc => c://my_docs/happy_flag_day/12_doc
spaces => spaces
Testing function allsep_to_kebab_case:
snakeCase => snake-case
snake_case => snake-case
snake-case => snake-case
snake case => snake-case
snake CASE => snake-case
snake.case => snake-case
variable_10_case => variable-10-case
variable10Case => variable10-case
ergo rE tHis => ergo-r-e-t-his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy-flag-day/12-doc
spaces => spaces
Testing function allsep_to_space_case:
snakeCase => snake case
snake_case => snake case
snake-case => snake case
snake case => snake case
snake CASE => snake case
snake.case => snake case
variable_10_case => variable 10 case
variable10Case => variable10 case
ergo rE tHis => ergo r e t his
hurry-up-joe! => hurry up joe!
c://my-docs/happy_Flag-Day/12.doc => c://my docs/happy flag day/12 doc
spaces => spaces
Testing function allsep_to_period_case:
snakeCase => snake.case
snake_case => snake.case
snake-case => snake.case
snake case => snake.case
snake CASE => snake.case
snake.case => snake.case
variable_10_case => variable.10.case
variable10Case => variable10.case
ergo rE tHis => ergo.r.e.t.his
hurry-up-joe! => hurry.up.joe!
c://my-docs/happy_Flag-Day/12.doc => c://my.docs/happy.flag.day/12.doc
spaces => spaces
Testing function allsep_to_slash_case:
snakeCase => snake/case
snake_case => snake/case
snake-case => snake/case
snake case => snake/case
snake CASE => snake//case
snake.case => snake/case
variable_10_case => variable/10/case
variable10Case => variable10/case
ergo rE tHis => ergo/r/e/t/his
hurry-up-joe! => hurry/up/joe!
c://my-docs/happy_Flag-Day/12.doc => c:/my/docs/happy//flag//day/12/doc
spaces => spaces
ALGOL 68
Treating space, - and _ as equivalent "break" characters (as in most of the other samples) and adding kebab case (as in the Raku sample) and resisting the urge to add "space case" for languages like Algol 68 where (insignificant) spaces can appear in identifiers...
BEGIN # convert camel case to and from snake case #
# returns c converted to uppercase if it is lowercase, c otherwise #
OP TOUPPER = ( CHAR c )STRING:
IF c >= "a" AND c <= "z" THEN REPR( ( ABS c - ABS "a" ) + ABS "A" ) ELSE c FI;
# returns c converted to lowercase if it is uppercase, c otherwise #
OP TOLOWER = ( CHAR c )STRING:
IF c >= "A" AND c <= "Z" THEN REPR( ( ABS c - ABS "A" ) + ABS "a" ) ELSE c FI;
# returns the camel case identifier c in snake case #
OP CAMELTOSNAKE = ( STRING c )STRING: c CAMELTOBREAK "_";
# returns the camel case identifier c in kebab case #
OP CAMELTOKEBAB = ( STRING c )STRING: c CAMELTOBREAK "-";
# returns TRUE if c is a "break" character ( " ", "-" or "_" ), FALSE otherwise #
OP ISBREAK = ( CHAR c )BOOL: c = " " OR c = "-" OR c = "_";
# returns the indentifier id (which is assumed to be in Camel case) #
# converted to snake or kebab case depending on break char #
PRIO CAMELTOBREAK = 9; # CAMELTOBREAK is dyadic so need a priority #
OP CAMELTOBREAK = ( STRING id, CHAR break char )STRING:
BEGIN
STRING result := "";
STRING orig = TRIM id; # remove leading and trailing spaces #
BOOL first := TRUE;
INT c pos := LWB orig;
WHILE c pos <= UPB orig DO
CHAR c = orig[ c pos ];
IF c >= "A" AND c <= "Z" THEN
# have an uppercase letter #
IF NOT first THEN result +:= break char FI;
result +:= TOLOWER c
ELIF ISBREAK c THEN
# replace one or more spaces and break characters by a single break #
BOOL have break := TRUE;
WHILE c pos <= UPB orig AND have break DO
IF have break := ISBREAK orig[ c pos ] THEN c pos +:= 1 FI
OD;
IF c pos <= UPB orig THEN
# the identifier didn't end wih a break #
result +:= break char + TOLOWER orig[ c pos ]
FI
ELSE
# lowercase or punctuation #
result +:= c
FI;
first := FALSE;
c pos +:= 1
OD;
result
END # CAMELTOBREAK # ;
# returns the identifier id ( which is assumed to be in snake/kebab/space case ) #
# converted to Camel case #
OP TOCAMEL = ( STRING id )STRING:
BEGIN
STRING result := "";
STRING orig = TRIM id; # remove leading and trailing spaces #
INT c pos := LWB orig;
WHILE c pos <= UPB orig DO
CHAR c = orig[ c pos ];
IF c >= "A" AND c <= "Z" THEN
# uppercase letter - leave as is #
result +:= c
ELIF NOT ISBREAK c THEN
# not a break - convert to lower case if necessary and move to the next #
result +:= TOLOWER c;
ELSE
# have a separator - skip all subsequent separators and upcase the follower #
BOOL have break := TRUE;
WHILE c pos <= UPB orig AND have break DO
IF have break := ISBREAK orig[ c pos ] THEN c pos +:= 1 FI
OD;
IF c pos <= UPB orig THEN
# the identifier didn't end with a break character #
result +:= TOUPPER orig[ c pos ]
FI
FI;
c pos +:= 1
OD;
result
END # TOCAMEL # ;
# returns s left-padded to len characters or s if s is already that long #
PRIO PAD = 9;
OP PAD = ( INT len, STRING s )STRING:
IF INT s len = ( UPB s - LWB s ) + 1;
s len >= len
THEN s
ELSE
STRING result := s;
FOR i FROM s len + 1 TO len DO " " +=: result OD;
result
FI # PAD # ;
# returns s with leading and trailing spaces removed #
OP TRIM = ( STRING s )STRING:
BEGIN
INT left := LWB s;
INT right := UPB s;
WHILE IF left > right THEN FALSE ELSE s[ left ] = " " FI DO left +:= 1 OD;
WHILE IF right < left THEN FALSE ELSE s[ right ] = " " FI DO right -:= 1 OD;
s[ left : right ]
END # TRIM # ;
# task test cases #
[]STRING identifier = ( "snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis"
, "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
);
print( ( "to snake case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", CAMELTOSNAKE identifier[ i ], newline ) )
OD;
print( ( "to Camel case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", TOCAMEL identifier[ i ], newline ) )
OD;
print( ( "to kebab case:", newline ) );
FOR i FROM LWB identifier TO UPB identifier DO
print( ( 40 PAD identifier[ i ], " -> ", CAMELTOKEBAB identifier[ i ], newline ) )
OD
END- Output:
to snake case:
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
╔ørgo rE tHis -> ╔ørgo_r_e_t_his
hurry-up-joe! -> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc
spaces -> spaces
to Camel case:
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
╔ørgo rE tHis -> ╔ørgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
to kebab case:
snakeCase -> snake-case
snake_case -> snake-case
variable_10_case -> variable-10-case
variable10Case -> variable10-case
╔ørgo rE tHis -> ╔ørgo-r-e-t-his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy-flag-day/12.doc
spaces -> spaces
Arturo
camelToSnake: function [str][
i: new 0
result: new ""
while [i < size str][
ch: str\[i]
if? upper? ch [
'result ++ `_` ++ lower str\[i]
]
else [
'result ++ str\[i]
]
inc 'i
]
return result
]
snakeToCamel: function [str][
i: new 0
result: new ""
while [i < size str][
ch: str\[i]
if? and? [ch=`_`][(i+1) < size str] [
'result ++ upper str\[i+1]
inc 'i
]
else [
'result ++ str\[i]
]
inc 'i
]
return result
]
tests: ["snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "]
loop tests 'test [
print [pad test 35 "=> camel:" snakeToCamel test "snake:" camelToSnake test]
]
- Output:
snakeCase => camel: snakeCase snake: snake_case
snake_case => camel: snakeCase snake: snake_case
variable_10_case => camel: variable10Case snake: variable_10_case
variable10Case => camel: variable10Case snake: variable10_case
ɛrgo rE tHis => camel: ɛrgo rE tHis snake: ɛrgo r_e t_his
hurry-up-joe! => camel: hurry-up-joe! snake: hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => camel: c://my-docs/happyFlag-Day/12.doc snake: c://my-docs/happy__flag-_day/12.doc
spaces => camel: spaces snake: spaces
C++
The output of this example reflects the author's interpretation of the task.
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
const char HYPHEN = '-';
const char SPACE = ' ';
const char UNDERSCORE = '_';
const std::string WHITESPACE = " \n\r\t\f\v";
std::string left_trim(const std::string& text) {
size_t start = text.find_first_not_of(WHITESPACE);
return ( start == std::string::npos ) ? "" : text.substr(start);
}
std::string right_trim(const std::string& text) {
size_t end = text.find_last_not_of(WHITESPACE);
return ( end == std::string::npos ) ? "" : text.substr(0, end + 1);
}
std::string trim(const std::string& text) {
return left_trim(right_trim(text));
}
void prepare_for_conversion(std::string& text) {
text = trim(text);
std::replace(text.begin(), text.end(), SPACE, UNDERSCORE);
std::replace(text.begin(), text.end(), HYPHEN, UNDERSCORE);
}
std::string to_snake_case(std::string& camel) {
prepare_for_conversion(camel);
std::string snake = "";
bool first = true;
for ( const char& ch : camel ) {
if ( first ) {
snake += ch;
first = false;
} else if ( ! first && ch >= 'A' && ch <= 'Z' ) {
if ( snake[snake.length() - 1] == UNDERSCORE ) {
snake += tolower(ch);
} else {
snake += UNDERSCORE;
snake += tolower(ch);
}
} else {
snake += ch;
}
}
return snake;
}
std::string to_camel_case(std::string& snake) {
prepare_for_conversion(snake);
std::string camel = "";
bool underscore = false;
for ( const char& ch : snake ) {
if ( ch == UNDERSCORE ) {
underscore = true;
} else if ( underscore ) {
camel += toupper(ch);
underscore = false;
} else {
camel += ch;
}
}
return camel;
}
int main() {
const std::vector<std::string> variable_names = { "snakeCase", "snake_case", "variable_10_case",
"variable10Case", "ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces " };
std::cout << std::setw(48) << "=== To snake_case ===" << std::endl;
for ( std::string text : variable_names ) {
std::cout << std::setw(34) << text << " --> " << to_snake_case(text) << std::endl;
}
std::cout << std::endl;
std::cout << std::setw(48) << "=== To camelCase ===" << std::endl;
for ( std::string text : variable_names ) {
std::cout << std::setw(34) << text << " --> " << to_camel_case(text) << std::endl;
}
}
- Output:
=== To snake_case ===
snakeCase --> snake_case
snake_case --> snake_case
variable_10_case --> variable_10_case
variable10Case --> variable10_case
ergo rE tHis --> ergo_r_e_t_his
hurry-up-joe! --> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc --> c://my_docs/happy_flag_day/12.doc
spaces --> spaces
=== To camelCase ===
snakeCase --> snakeCase
snake_case --> snakeCase
variable_10_case --> variable10Case
variable10Case --> variable10Case
ergo rE tHis --> ergoRETHis
hurry-up-joe! --> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc --> c://myDocs/happyFlagDay/12.doc
spaces --> spaces
Delphi
Makes use of Delphi "sets" to help parse strings.
const TestStrings: array [0..7] of string = (
'snakeCase', 'snake_case', 'variable_10_case', 'variable10Case',
'\u025brgo rE tHis', 'hurry-up-joe!', 'c://my-docs/happy_Flag-Day/12.doc',
' spaces ');
function MakeCamelCase(S: string): string;
{Convert string to camel-case}
var I: integer;
var Toggle: boolean;
begin
S:=Trim(S);
Result:='';
for I:=1 to Length(S) do
if Toggle then
begin
Result:=Result+UpperCase(S[I]);
Toggle:=False;
end
else if S[I] in [' ','_','-'] then Toggle:=True
else Result:=Result+S[I];
end;
function MakeSnakeCase(S: string): string;
{Convert string to snake-case}
var I: integer;
var Toggle: boolean;
begin
S:=Trim(S);
Result:='';
for I:=1 to Length(S) do
if S[I] in [' ','-'] then Result:=Result+'_'
else if S[I] in ['A'..'Z'] then
begin
Result:=Result+'_';
Result:=Result+LowerCase(S[I]);
end
else Result:=Result+S[I];
end;
procedure ConvertCamelSnake(SA: array of string; Memo: TMemo);
var I: integer;
var S: string;
function FormatStrs(S1,S2: string): string;
begin
Result:=Format('%35s',[S1])+' '+Format('%-35s',[S2]);
end;
begin
Memo.Lines.Add('Snake Case: ');
for I:=0 to High(SA) do
begin
S:=FormatStrs(SA[I],MakeSnakeCase(SA[I]));
Memo.Lines.Add(S);
end;
Memo.Lines.Add('Camel Case: ');
for I:=0 to High(SA) do
begin
S:=FormatStrs(SA[I],MakeCamelCase(SA[I]));
Memo.Lines.Add(S);
end;
end;
procedure CamelSnakeTest(Memo: TMemo);
{Test camel/snake conversion routines}
begin
ConvertCamelSnake(TestStrings,Memo);
end;
- Output:
Snake Case:
snakeCase snake_case
snake_case snake_case
variable_10_case variable_10_case
variable10Case variable10_case
\u025brgo rE tHis \u025brgo_r_e_t_his
hurry-up-joe! hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc c://my_docs/happy__flag__day/12.doc
spaces spaces
Camel Case:
snakeCase snakeCase
snake_case snakeCase
variable_10_case variable10Case
variable10Case variable10Case
\u025brgo rE tHis \u025brgoRETHis
hurry-up-joe! hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc c://myDocs/happyFlagDay/12.doc
spaces spaces
EasyLang
func$ strip s$ .
a = 1
while substr s$ a 1 = " "
a += 1
.
b = len s$
while substr s$ b 1 = " "
b -= 1
.
return substr s$ a (b - a + 1)
.
func$ toupper c$ .
c = strcode c$
if c >= 97 and c <= 122
c$ = strchar (c - 32)
.
return c$
.
func$ tolower c$ .
c = strcode c$
if c >= 65 and c <= 90
c$ = strchar (c + 32)
.
return c$
.
func isupper c$ .
c = strcode c$
if c >= 65 and c <= 90
return 1
.
.
delim$ = "_- "
func$ snakecase s$ .
s$ = strip s$
for c$ in strchars s$
if isupper c$ = 1 and prev$ <> ""
if strpos delim$ prev$ = 0
r$ &= "_"
.
r$ &= tolower c$
else
r$ &= c$
.
prev$ = c$
.
return r$
.
func$ camelcase s$ .
s$ = strip s$
prev$ = "x"
for c$ in strchars s$
if strpos delim$ prev$ <> 0
r$ &= toupper c$
elif strpos delim$ c$ = 0
r$ &= c$
.
prev$ = c$
.
return r$
.
test$[] = [ "snakeCase" "snake_case" "variable_10_case" "variable10Case" "ɛrgo rE tHis" "hurry-up-joe!" "c://my-docs/happy_Flag-Day/12.doc" " spaces " ]
print "=== To snake_case ==="
for s$ in test$[]
print s$ & " -> " & snakecase s$
.
print "\n=== To camelCase ==="
for s$ in test$[]
print s$ & " -> " & camelcase s$
.- Output:
=== To snake_case === snakeCase -> snake_case snake_case -> snake_case variable_10_case -> variable_10_case variable10Case -> variable10_case ɛrgo rE tHis -> ɛrgo r_e t_his hurry-up-joe! -> hurry-up-joe! c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc spaces -> spaces === To camelCase === snakeCase -> snakeCase snake_case -> snakeCase variable_10_case -> variable10Case variable10Case -> variable10Case ɛrgo rE tHis -> ɛrgoRETHis hurry-up-joe! -> hurryUpJoe! c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc spaces -> spaces
Factor
In my interpretation of the task, leading/trailing whitespace should be ignored, not trimmed. And non-leading/trailing whitespace should be dealt with the same way as underscores and hyphens. Although the task says nothing about numbers, I chose to treat letter->number and number->letter transitions the same way as lower->upper for the sake of converting to snake case.
USING: formatting kernel math regexp sequences splitting
splitting.extras unicode ;
! ignore leading/trailing whitespace
: preserve ( str quot -- newstr )
[ [ blank? ] split-head [ blank? ] split-tail swap ] dip
call glue ; inline
: >snake ( str -- newstr )
[
R/ (\p{lower}\p{upper}|\d\p{alpha}|\p{alpha}\d)/
[ 1 short cut >lower "_" glue ] re-replace-with
R/ [\s-]/ "_" re-replace
] preserve ;
: capitalize ( str -- newstr ) 1 short cut swap >upper prepend ;
: >camel ( str -- newstr )
[
"\s_-" split harvest 1 short cut
[ capitalize ] map append "" join
] preserve ;
: test ( str -- )
dup >snake over dup >camel
"%u >snake %u\n%u >camel %u\n" printf ;
{
"snakeCase" "snake_case" "variable_10_case" "variable10Case"
"ɛrgo rE tHis" "hurry-up-joe!"
"c://my-docs/happy_Flag-Day/12.doc" " spaces "
" internal space "
} [ test ] each
- Output:
"snakeCase" >snake "snake_case" "snakeCase" >camel "snakeCase" "snake_case" >snake "snake_case" "snake_case" >camel "snakeCase" "variable_10_case" >snake "variable_10_case" "variable_10_case" >camel "variable10Case" "variable10Case" >snake "variable_10_case" "variable10Case" >camel "variable10Case" "ɛrgo rE tHis" >snake "ɛrgo_r_e_t_his" "ɛrgo rE tHis" >camel "ɛrgoRETHis" "hurry-up-joe!" >snake "hurry_up_joe!" "hurry-up-joe!" >camel "hurryUpJoe!" "c://my-docs/happy_Flag-Day/12.doc" >snake "c://my_docs/happy_Flag_Day/12.doc" "c://my-docs/happy_Flag-Day/12.doc" >camel "c://myDocs/happyFlagDay/12.doc" " spaces " >snake " spaces " " spaces " >camel " spaces " " internal space " >snake " internal_space " " internal space " >camel " internalSpace "
FreeBASIC
Function isDigit(ch As String) As Boolean
Return ch >= "0" And ch <= "9"
End Function
Function to_snake_case(s As String) As String
Dim As Integer l = Len(s)
Dim As String snake = Trim(s), tmp = snake
For i As Integer = 1 To Len(snake)
If isDigit(Mid(snake, i, 1)) Then
Continue For
Elseif Instr(Mid(snake, i, 1), " ") Then
Mid(snake, i) = "_"
Continue For
Elseif Instr(Mid(snake, i, 1), Any "\:/-_!.") Then
Continue For
Elseif Mid(snake, i, 1) = Ucase(Mid(snake, i, 1)) Then
tmp = Lcase(Mid(snake, i,1))
Mid(snake, i) = "_"
snake = Left(snake, i) & tmp & Mid(snake, i+1)
End If
Next i
Return snake
End Function
Function toCamelCase(s As String) As String
Dim As Integer l = Len(s)
Dim As String camel = Trim(s), tmp = camel
For i As Integer = 1 To Len(camel)
If Instr(Mid(camel, i, 1), Any ":/!.") Then
Continue For
Elseif Instr(Mid(camel, i, 1), Any " _-") Then
camel = Left(camel, i-1) & Ucase(Mid(camel, i+1,1)) & Mid(camel, i+2)
End If
Next i
Return camel
End Function
Dim Shared tests(1 To ...) As String*33 => {_
"snakeCase", "snake_case", "variable_10_case", "variable10Case", _
"\u025brgo rE tHis", "ergo rE tHis", "hurry-up-joe!", _
"c://my-docs/happy_Flag-Day/12.doc", " spaces "}
Sub test0(title As String, fn As String)
Print title
For i As Integer = 1 To Ubound(tests)
Dim As String texto = tests(i) & " ===> " & to_snake_case(tests(i))
Locate i+1, 41 - Len(texto) / 2 : Print texto
Next i
End Sub
Sub test1(title As String, fn As String)
Print title
For i As Integer = 1 To Ubound(tests)
Dim As String texto = tests(i) & " ===> " & toCamelCase(tests(i))
Locate i+12, 41 - Len(texto) / 2 : Print texto
Next i
End Sub
test0 "to_snake_case:", "to_snake_case"
Print
test1 "toCamelCase:", "toCamelCase"
SleepFutureBasic
include "NSLog.incl"
local fn snake_toCamel( s as CFStringRef ) as CFStringRef
long r,f
s = fn StringByTrimmingCharactersInSet( s, fn CFCharacterSetGetPredefined(_kCFCharacterSetWhitespace ))
for r = 1 to len(s)-2
f = instr(0, @"_- ", mid(s, r, 1))
if f <> NSNotFound
s = fn stringwithformat(@"%@%@%@", left( s, r ), ucase(mid(s,r+1,1)), mid(s,r+2))
end if
next
end fn = s
local fn CamelTo_snake( s as CFStringRef ) as CFStringRef
long r,f
s = fn StringByTrimmingCharactersInSet( s, fn CFCharacterSetGetPredefined(_kCFCharacterSetWhitespace ))
s = fn StringByReplacingOccurrencesOfString( s, @" ", @"_")
s = fn StringByReplacingOccurrencesOfString( s, @"-", @"_")
for r = 1 to len(s)-2
f = instr(0, @"ABCDEFGHIJKLMNOPQRSTUVWXYZ", mid(s, r, 1))
if f <> NSNotFound
if fn StringIsEqual(@"_", mid(s, r-1, 1)) then continue
s = fn stringwithformat(@"%@%@%@", left( s, r ), @"_", mid(s,r))
end if
next
s = fn stringwithformat(@"%@%@",left( s, 1), lcase(mid(s, 1)))
end fn = s
local fn show( s1 as CFStringRef )
CFStringRef s = @" "
CFStringRef s2 = fn snake_toCamel( s1 )
CFStringRef s3 = fn CamelTo_snake( s1 )
nslog(@" \"%@\"%@\"%@\"%@\"%@\"", s1, mid(s, len(s1)), s2, mid(s, len(s2)), s3)
end fn
nslog( @"%@",@"String ¬
fn snake_toCamel ¬
fn CamelTo_snake")
fn show(@"snakeCase")
fn show(@"snake_case")
fn show(@"variable_10_case")
fn show(@"variable10Case")
fn show(@"ɛrgo rE tHis")
fn show(@"hurry-up-joe!")
fn show(@"c://my-docs/happy_Flag-Day/12.doc")
fn show(@" spaces ")
handleevents- Output:
String fn snake_toCamel fn CamelTo_snake
"snakeCase" "snakeCase" "snake_case"
"snake_case" "snakeCase" "snake_case"
"variable_10_case" "variable10Case" "variable_10_case"
"variable10Case" "variable10Case" "variable10_case"
"ɛrgo rE tHis" "ɛrgoRETHis" "ɛrgo_r_e_t_his"
"hurry-up-joe!" "hurryUpJoe!" "hurry_up_joe!"
" spaces " "spaces" "spaces"
"c://my-docs/happy_Flag-Day/12.doc" "c://myDocs/happyFlagDay/12.doc" "c://my_docs/happy_flag_day/12.doc"Java
The output of this example reflects the authors interpretation of the task.
import java.util.List;
public final class CamelCaseAndSnakeCase {
public static void main(String[] aArgs) {
List<String> variableNames = List.of( "snakeCase", "snake_case", "variable_10_case", "variable10Case",
"ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces ");
System.out.println(String.format("%48s", "=== To snake_case ==="));
for ( String text : variableNames ) {
System.out.println(String.format("%34s%s%s", text, " --> ", toSnakeCase(text)));
}
System.out.println();
System.out.println(String.format("%48s", "=== To camelCase ==="));
for ( String text : variableNames ) {
System.out.println(String.format("%34s%s%s", text, " --> ", toCamelCase(text)));
}
}
private static String toSnakeCase(String aCamel) {
aCamel = aCamel.trim().replace(SPACE, UNDERSCORE).replace(HYPHEN, UNDERSCORE);
StringBuilder snake = new StringBuilder();
boolean first = true;
for ( char ch : aCamel.toCharArray() ) {
if ( first ) {
snake.append(ch);
first = false;
} else if ( ! first && Character.isUpperCase(ch) ) {
if ( snake.toString().endsWith(UNDERSCORE) ) {
snake.append(Character.toLowerCase(ch));
} else {
snake.append(UNDERSCORE + Character.toLowerCase(ch));
}
} else {
snake.append(ch);
}
}
return snake.toString();
}
private static String toCamelCase(String aSnake) {
aSnake = aSnake.trim().replace(SPACE, UNDERSCORE).replace(HYPHEN, UNDERSCORE);
StringBuilder camel = new StringBuilder();
boolean underscore = false;
for ( char ch : aSnake.toCharArray() ) {
if ( Character.toString(ch).equals(UNDERSCORE) ) {
underscore = true;
} else if ( underscore ) {
camel.append(Character.toUpperCase(ch));
underscore = false;
} else {
camel.append(ch);
}
}
return camel.toString();
}
private static final String SPACE = " ";
private static final String UNDERSCORE = "_";
private static final String HYPHEN = "-";
}
- Output:
=== To snake_case ===
snakeCase --> snake_case
snake_case --> snake_case
variable_10_case --> variable_10_case
variable10Case --> variable10_case
ergo rE tHis --> ergo_r_e_t_his
hurry-up-joe! --> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc --> c://my_docs/happy_flag_day/12.doc
spaces --> spaces
=== To camelCase ===
snakeCase --> snakeCase
snake_case --> snakeCase
variable_10_case --> variable10Case
variable10Case --> variable10Case
ergo rE tHis --> ergoRETHis
hurry-up-joe! --> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc --> c://myDocs/happyFlagDay/12.doc
spaces --> spaces
jq
Adapted from Wren
Works with gojq, the Go implementation of jq
Preliminaries
def isUpper: explode[0] | 65 <= . and . <= 90;
def lpad($len): tostring | ($len - length) as $l | (" " * $l)[:$l] + .;
# "White space is not permitted as part of camel case or snake case variable names."
def trim: sub("^\\s+";"") | sub("\\s+$";"");Camel and Snake
def toCamel:
trim as $snake
| { camel: "", underscore : false}
| reduce ($snake|explode[]|[.]|implode) as $c (.;
if ["_", "-", " "]|index($c)
then .underscore = true
elif .underscore
then .camel += ($c|ascii_upcase)
| .underscore = false
else .camel += $c
end)
| .camel;
def toSnake:
(trim | gsub("\\s"; "_")) as $camel
| reduce ($camel|explode[1:][]|[.]|implode) as $c (
$camel[0:1];
if $c|isUpper
then ($c|ascii_downcase) as $lc
| if (.[-1:] | (. == "_" or . == "-"))
then . + $lc
else . + "_" + $lc
end
else . + $c
end );
def tests: [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
];
" === to_snake_case ===",
(tests[] | "\(lpad(33)) -> \(toSnake)"),
"",
" === toCamelCase ===",
(tests[] | "\(lpad(33)) -> \(toCamel)")- Output:
=== to_snake_case ===
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
ɛrgo rE tHis -> ɛrgo_r_e_t_his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc
spaces -> spaces
=== toCamelCase ===
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
ɛrgo rE tHis -> ɛrgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
Julia
#=
Regex based variable name convention change string functions.
`sep` is the separator targeted for change from (to camel case) or to (to snake case)
`allsep` is the separators other than `sep` that may be changed to `sep`
`lcmiddle` is a boolean to set whether caps within camel case words are made lowercase
=#
function snakeToCamelCase(s; sep=r"[_]+", lcmiddle=false)
isempty(s) && return s
words = split(strip(s), sep)
return lowercasefirst(join(uppercasefirst.(lcmiddle ? lowercase.(words) : words)))
end
spaceToCamelCase(s) = snakeToCamelCase(s; sep=r"\s+")
kebabToCamelCase(s) = snakeToCamelCase(s; sep=r"[\-]+")
periodToCamelCase(s) = snakeToCamelCase(s; sep=r"[\.]+")
allsepToCamelCase(s) = snakeToCamelCase(s; sep=r"[ \-_\.]+")
lowermiddle_allsepToCamelCase(s) = snakeToCamelCase(s; sep=r"[ \-_\.]+", lcmiddle=true)
function camel_to_snake_case(s; sep="_", insep=sep, allsep=r"_+", lcmiddle=true)
s = isempty(s) ? (return s) : lowercasefirst(strip(s))
s = replace(s, r"[A-Z]+" => x -> sep * (lcmiddle ? lowercase(x) : lowercasefirst(x)))
return replace(s, allsep => sep)
end
preserve_midcaps_camel_to_snake_case(s) = camel_to_snake_case(s; lcmiddle=false)
allsep_to_snake_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+")
allsep_to_kebab_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep="-")
allsep_to_space_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep=" ")
allsep_to_period_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep=".")
allsep_to_slash_case(s) = camel_to_snake_case(s; allsep=r"[ \-\._]+", sep="/")
for f in [
snakeToCamelCase,
spaceToCamelCase,
kebabToCamelCase,
periodToCamelCase,
allsepToCamelCase,
lowermiddle_allsepToCamelCase,
camel_to_snake_case,
preserve_midcaps_camel_to_snake_case,
allsep_to_snake_case,
allsep_to_kebab_case,
allsep_to_space_case,
allsep_to_period_case,
allsep_to_slash_case,
]
println("Testing function $f:")
for teststring in [
"snakeCase",
"snake_case",
"snake-case",
"snake case",
"snake CASE",
"snake.case",
"variable_10_case",
"variable10Case",
"ɛrgo rE tHis",
"hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc",
" spaces ",
]
println(lpad(teststring, 36), " => ", f(teststring))
end
println()
end
- Output:
Testing function snakeToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
Testing function spaceToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
Testing function kebabToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snakeCase
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
Testing function periodToCamelCase:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snakeCase
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12Doc
spaces => spaces
Testing function allsepToCamelCase:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function lowermiddle_allsepToCamelCase:
snakeCase => snakecase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCase
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10case
ɛrgo rE tHis => ɛrgoReThis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _case
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function preserve_midcaps_camel_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _cASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function allsep_to_snake_case:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake_case
snake case => snake_case
snake CASE => snake_case
snake.case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo_r_e_t_his
hurry-up-joe! => hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc => c://my_docs/happy_flag_day/12_doc
spaces => spaces
Testing function allsep_to_kebab_case:
snakeCase => snake-case
snake_case => snake-case
snake-case => snake-case
snake case => snake-case
snake CASE => snake-case
snake.case => snake-case
variable_10_case => variable-10-case
variable10Case => variable10-case
ɛrgo rE tHis => ɛrgo-r-e-t-his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy-flag-day/12-doc
spaces => spaces
Testing function allsep_to_space_case:
snakeCase => snake case
snake_case => snake case
snake-case => snake case
snake case => snake case
snake CASE => snake case
snake.case => snake case
variable_10_case => variable 10 case
variable10Case => variable10 case
ɛrgo rE tHis => ɛrgo r e t his
hurry-up-joe! => hurry up joe!
c://my-docs/happy_Flag-Day/12.doc => c://my docs/happy flag day/12 doc
spaces => spaces
Testing function allsep_to_period_case:
snakeCase => snake.case
snake_case => snake.case
snake-case => snake.case
snake case => snake.case
snake CASE => snake.case
snake.case => snake.case
variable_10_case => variable.10.case
variable10Case => variable10.case
ɛrgo rE tHis => ɛrgo.r.e.t.his
hurry-up-joe! => hurry.up.joe!
c://my-docs/happy_Flag-Day/12.doc => c://my.docs/happy.flag.day/12.doc
spaces => spaces
Testing function allsep_to_slash_case:
snakeCase => snake/case
snake_case => snake/case
snake-case => snake/case
snake case => snake/case
snake CASE => snake//case
snake.case => snake/case
variable_10_case => variable/10/case
variable10Case => variable10/case
ɛrgo rE tHis => ɛrgo/r/e/t/his
hurry-up-joe! => hurry/up/joe!
c://my-docs/happy_Flag-Day/12.doc => c://my/docs/happy//flag//day/12/doc
spaces => spaces
Kotlin
fun main() {
val variableNames = listOf("snakeCase", "snake_case", "variable_10_case", "variable10Case",
"ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces ")
println(" ".repeat(26) + "=== To snake_case ===")
variableNames.forEach { text ->
println("${text.padStart(34)} --> ${toSnakeCase(text)}")
}
println("\n" + " ".repeat(26) + "=== To camelCase ===")
variableNames.forEach { text ->
println("${text.padStart(34)} --> ${toCamelCase(text)}")
}
}
fun toSnakeCase(camel: String): String {
val snake = StringBuilder()
camel.trim().replace(" ", "_").replace("-", "_").forEach { ch ->
if (snake.isEmpty() || snake.last() != '_' || ch != '_') {
if (ch.isUpperCase() && snake.isNotEmpty() && snake.last() != '_') snake.append('_')
snake.append(ch.toLowerCase())
}
}
return snake.toString()
}
fun toCamelCase(snake: String): String {
val camel = StringBuilder()
var underscore = false
snake.trim().replace(" ", "_").replace("-", "_").forEach { ch ->
if (ch == '_') {
underscore = true
} else if (underscore) {
camel.append(ch.toUpperCase())
underscore = false
} else {
camel.append(ch)
}
}
return camel.toString()
}
- Output:
=== To snake_case ===
snakeCase --> snake_case
snake_case --> snake_case
variable_10_case --> variable_10_case
variable10Case --> variable10_case
ergo rE tHis --> ergo_r_e_t_his
hurry-up-joe! --> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc --> c://my_docs/happy_flag_day/12.doc
spaces --> spaces
=== To camelCase ===
snakeCase --> snakeCase
snake_case --> snakeCase
variable_10_case --> variable10Case
variable10Case --> variable10Case
ergo rE tHis --> ergoRETHis
hurry-up-joe! --> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc --> c://myDocs/happyFlagDay/12.doc
spaces --> spaces
Lambdatalk
{def snake2camel
{lambda {:w}
{S.replace (?:_|-)(\w)
by {span {@ style="text-transform:uppercase;"}$1}
in :w}}}
-> snake2camel
{def camel2snake
{lambda {:w}
{S.replace ([A-Z])
by _{span {@ style="text-transform:lowercase;"}$1}
in :w}}}
-> camel2snake
{S.map snake2camel
snake_case
snake-case
my_brave_new_world
my_brave-new_world
... and_so_on
}
-> snakeCase snakeCase myBraveNewWorld myBraveNewWorld ... andSoOn
{S.map camel2snake
snakeCase
myBraveNewWorld
... andSoOn
}
-> snake_case my_brave_new_world ... and_so_on
Lua
Since the task is a bit vague this solution also has its own interpretation of several details.
We have the two functions toCamelCase() and fromCamelCase() that perform the conversion back and forth between camel case and non-camel case, including snake case. The test strings are assumed to potentially contain multiple names. Any character that isn't part of the matched names (including leading and trailing whitespace) is ignored/left alone. Numbers aren't mentioned in the task but the "variable_10_case"/"variable10Case" strings imply that numbers should be treated as their own words.
local function escapeForPattern(str)
return (str:gsub("[-+*^?$.%%()[%]]", "%%%0"))
end
local function toCamelCase(str, separator)
local escapedSeparator = escapeForPattern(separator)
local namePattern = "%l%w*"..escapedSeparator.."[%w"..escapedSeparator.."]*%w" -- Starting with a lower case character and containing the separator character.
local separatorPattern = escapedSeparator.."(%w)" -- Discard the separator and capture the alphanumeric character.
return (str:gsub(namePattern, function(name)
return (name:gsub(separatorPattern, string.upper)) -- The captured character will be the one argument for string.upper().
end))
end
local function fromCamelCase(str, separator)
local namePattern = "%l+[%u%d]%w*" -- Starting with a lower case character and containing an upper case character or digit.
local separatorPattern1 = "(%l)([%u%d])" -- Lower case character followed by upper case character or digit.
local separatorPattern2 = "(%d)(%a)" -- Digit followed by alphanumeric character.
return (str:gsub(namePattern, function(name)
return (name
:gsub(separatorPattern1, function(char1,char2) return char1..separator..char2:lower() end)
:gsub(separatorPattern2, function(char1,char2) return char1..separator..char2:lower() end)
)
end))
end
Tests:
local function utf8Length(str)
local len = 0
for char in str:gmatch"[\1-\127\194-\244][\128-\191]*" do
len = len + 1
end
return len
end
local tests = {
"snakeCase", "snake_case",
"variable_10_case", "variable10Case",
"ɛrgo rE tHis",
"hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc",
" spaces ",
" internal space ",
}
local function convert(label, converter)
print(label..":")
for _, str in ipairs(tests) do
print((" "):rep(35-utf8Length(str)) .. str .. " => " .. converter(str))
end
print()
end
convert("snake_case to camelCase", function(str) return toCamelCase (str, "_") end)
convert("space case to camelCase", function(str) return toCamelCase (str, " ") end)
convert("kebab-case to camelCase", function(str) return toCamelCase (str, "-") end)
convert("camelCase to snake_case", function(str) return fromCamelCase(str, "_") end)
- Output:
snake_case to camelCase:
snakeCase => snakeCase
snake_case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
internal space => internal space
space case to camelCase:
snakeCase => snakeCase
snake_case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
internal space => internalSpace
kebab-case to camelCase:
snakeCase => snakeCase
snake_case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
internal space => internal space
camelCase to snake_case:
snakeCase => snake_case
snake_case => snake_case
variable_10_case => variable_10_case
variable10Case => variable_10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
internal space => internal space
Notes:
- We don't check if names have preceding alphanumeric characters (e.g. "10kN" will have the name "kN").
- We don't handle consecutive upper case characters (e.g. "newUIBox").
- We don't handle non-ASCII characters because of Lua's limited support for them ("ɛ" just happen to work here).
Nim
We use the same rules as those used by Wren's solution.
import std/[strformat, strutils, unicode]
const Delimiters = [Rune('_'), Rune('-'), Rune(' ')]
func toCamelCase(s: string): string =
let s = s.strip(chars = Whitespace)
var prev = Rune(0)
for rune in s.runes:
if prev in Delimiters:
result.add rune.toUpper
elif rune notin Delimiters:
result.add rune
prev = rune
func toSnakeCase(s: string): string =
var s= s.strip(chars = Whitespace).replace(' ', '_')
var idx = 0
var prev = Rune(0)
for rune in s.runes:
if rune.isUpper and idx > 0:
if prev notin Delimiters:
result.add '_'
result.add rune.toLower
else:
result.add rune
prev = rune
inc idx
const Strings = ["snakeCase", "snake_case", "variable_10_case",
"variable10Case", "ɛrgo rE tHis", "hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc", " spaces "]
echo center("### To snake case ###", 69)
for s in Strings:
echo &"{s:>33} → {s.toSnakeCase}"
echo()
echo center("### To camel case ###", 69)
for s in Strings:
echo &"{s:>33} → {s.toCamelCase}"
- Output:
### To snake case ###
snakeCase → snake_case
snake_case → snake_case
variable_10_case → variable_10_case
variable10Case → variable10_case
ɛrgo rE tHis → ɛrgo_r_e_t_his
hurry-up-joe! → hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc → c://my-docs/happy_flag-day/12.doc
spaces → spaces
### To camel case ###
snakeCase → snakeCase
snake_case → snakeCase
variable_10_case → variable10Case
variable10Case → variable10Case
ɛrgo rE tHis → ɛrgoRETHis
hurry-up-joe! → hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc → c://myDocs/happyFlagDay/12.doc
spaces → spaces
Perl
#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Camel_case_and_snake_case
use warnings;
my @words = (
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "#rgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
);
sub tosnake
{
shift =~ s/^ +| +$//gr =~ s/[A-Z]/_\l$&/gr =~ tr/ -/_/r =~ s/__+/_/gr;
}
sub tocamel
{
shift =~ s/^ +| +$//gr =~ s/[ _-]([a-z0-9])/\u$1/gir;
}
print "to snake case\n\n";
for my $word ( @words )
{
printf "%35s -> %s\n", $word, tosnake($word);
}
print "\nto camel case\n\n";
for my $word ( @words )
{
printf "%35s -> %s\n", $word, tocamel($word);
}
- Output:
to snake case
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
#rgo rE tHis -> #rgo_r_e_t_his
hurry-up-joe! -> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc
spaces -> spaces
to camel case
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
#rgo rE tHis -> #rgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
Phix
with javascript_semantics function to_snake_case(string s) string snake = substitute(trim(s)," ","_") for i=length(snake) to 1 by -1 do if isupper(snake[i]) then snake[i..i] = '_'&lower(snake[i]) end if end for return snake end function function toCamelCase(string s) string camel = substitute_all(trim(s),"- ","__") for i=length(camel)-1 to 1 by -1 do if camel[i]='_' then camel[i..i+1] = upper(camel[i+1..i+1]) end if end for return camel end function constant tests = {"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "} procedure test(string title, integer fn) printf(1,title) for i=1 to length(tests) do printf(1,"%33s ===> %s\n", {tests[i], fn(tests[i])}) end for end procedure test(" === to_snake_case ===\n",to_snake_case) test("\n === toCamelCase ===\n",toCamelCase)
- Output:
=== to_snake_case ===
snakeCase ===> snake_case
snake_case ===> snake_case
variable_10_case ===> variable_10_case
variable10Case ===> variable10_case
ergo rE tHis ===> ergo_r_e_t_his
hurry-up-joe! ===> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ===> c://my-docs/happy__flag-_day/12.doc
spaces ===> spaces
=== toCamelCase ===
snakeCase ===> snakeCase
snake_case ===> snakeCase
variable_10_case ===> variable10Case
variable10Case ===> variable10Case
ergo rE tHis ===> ergoRETHis
hurry-up-joe! ===> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc ===> c://myDocs/happyFlagDay/12.doc
spaces ===> spaces
Python
""" https://rosettacode.org/wiki/Camel_case_and_snake_case """
import re
def snakeToCamelCase(nam, sep='[_]+', lcmiddle=False):
""" convert snake '_' separator case to camel case """
if nam == '':
return nam
words = re.split(sep, nam.strip())
if lcmiddle:
words = [w.lower() for w in words]
words[1:] = [w[0].upper() + w[1:] for w in words[1:] if len(w) > 0]
return ''.join(words)
def spaceToCamelCase(nam):
""" convert space case to camel case """
return snakeToCamelCase(nam, sep='\s+')
def kebabToCamelCase(nam):
""" convert kebab '-' case to camel case """
return snakeToCamelCase(nam, sep='[\-]+')
def periodToCamelCase(nam):
""" convert period '.' case to camel case """
return snakeToCamelCase(nam, sep='[\.]+')
def allsepToCamelCase(nam):
""" convert all separators in allsep to camel case """
return snakeToCamelCase(nam, sep='[ \-_\.]+')
def lowermiddle_allsepToCamelCase(nam):
""" convert all separators to camel case, and all but word starts to lowercase """
return snakeToCamelCase(nam, sep='[ \-_\.]+', lcmiddle=True)
def camel_to_snake_case(nam, sep='_', allsep='[_]+', lcmiddle=True):
""" convert camel case to snake case (separate with '_') """
nam = re.sub('([A-Z]+)', sep + r"\1", nam.strip())
sep1 = '\\' + sep if sep == '.' else sep
if lcmiddle:
nam = sep.join([w.lower() for w in nam.split(sep1) if len(w) > 0])
else:
nam = sep.join([w[0].lower() + w[1:] for w in nam.split(sep1) if len(w) > 0])
return re.sub(allsep, sep, nam)
def preserve_midcaps_camel_to_snake_case(nam):
return camel_to_snake_case(nam, lcmiddle=False)
def allsep_to_snake_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+')
def allsep_to_kebab_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='-')
def allsep_to_space_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep=' ')
def allsep_to_period_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='.')
def allsep_to_slash_case(nam):
return camel_to_snake_case(nam, allsep='[ \-\._]+', sep='/')
for f in [
snakeToCamelCase,
spaceToCamelCase,
kebabToCamelCase,
periodToCamelCase,
allsepToCamelCase,
lowermiddle_allsepToCamelCase,
camel_to_snake_case,
preserve_midcaps_camel_to_snake_case,
allsep_to_snake_case,
allsep_to_kebab_case,
allsep_to_space_case,
allsep_to_period_case,
allsep_to_slash_case]:
print(f"Testing function {f}:")
for teststring in [
"snakeCase",
"snake_case",
"snake-case",
"snake case",
"snake CASE",
"snake.case",
"variable_10_case",
"variable10Case",
"ɛrgo rE tHis",
"hurry-up-joe!",
"c://my-docs/happy_Flag-Day/12.doc",
" spaces "]:
print(teststring.rjust(36), " => ", f(teststring))
print()
- Output:
Testing function <function snakeToCamelCase at 0x000001F17C25AC10>:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happyFlag-Day/12.doc
spaces => spaces
Testing function <function spaceToCamelCase at 0x000001F17C25AA60>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12.doc
spaces => spaces
Testing function <function kebabToCamelCase at 0x000001F17C25ADC0>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snakeCase
snake case => snake case
snake CASE => snake CASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happy_FlagDay/12.doc
spaces => spaces
Testing function <function periodToCamelCase at 0x000001F17C25AE50>:
snakeCase => snakeCase
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake CASE
snake.case => snakeCase
variable_10_case => variable_10_case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgo rE tHis
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_Flag-Day/12Doc
spaces => spaces
Testing function <function allsepToCamelCase at 0x000001F17C25AEE0>:
snakeCase => snakeCase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCASE
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10Case
ɛrgo rE tHis => ɛrgoRETHis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function <function lowermiddle_allsepToCamelCase at 0x000001F17C25AF70>:
snakeCase => snakecase
snake_case => snakeCase
snake-case => snakeCase
snake case => snakeCase
snake CASE => snakeCase
snake.case => snakeCase
variable_10_case => variable10Case
variable10Case => variable10case
ɛrgo rE tHis => ɛrgoReThis
hurry-up-joe! => hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc => c://myDocs/happyFlagDay/12Doc
spaces => spaces
Testing function <function camel_to_snake_case at 0x000001F17C262040>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _case
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function <function preserve_midcaps_camel_to_snake_case at 0x000001F17C2620D0>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake-case
snake case => snake case
snake CASE => snake _cASE
snake.case => snake.case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo r_e t_his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy_flag-_day/12.doc
spaces => spaces
Testing function <function allsep_to_snake_case at 0x000001F17C262160>:
snakeCase => snake_case
snake_case => snake_case
snake-case => snake_case
snake case => snake_case
snake CASE => snake_case
snake.case => snake_case
variable_10_case => variable_10_case
variable10Case => variable10_case
ɛrgo rE tHis => ɛrgo_r_e_t_his
hurry-up-joe! => hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc => c://my_docs/happy_flag_day/12_doc
spaces => spaces
Testing function <function allsep_to_kebab_case at 0x000001F17C2621F0>:
snakeCase => snake-case
snake_case => snake-case
snake-case => snake-case
snake case => snake-case
snake CASE => snake-case
snake.case => snake-case
variable_10_case => variable-10-case
variable10Case => variable10-case
ɛrgo rE tHis => ɛrgo-r-e-t-his
hurry-up-joe! => hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc => c://my-docs/happy-flag-day/12-doc
spaces => spaces
Testing function <function allsep_to_space_case at 0x000001F17C262280>:
snakeCase => snake case
snake_case => snake case
snake-case => snake case
snake case => snake case
snake CASE => snake case
snake.case => snake case
variable_10_case => variable 10 case
variable10Case => variable10 case
ɛrgo rE tHis => ɛrgo r e t his
hurry-up-joe! => hurry up joe!
c://my-docs/happy_Flag-Day/12.doc => c://my docs/happy flag day/12 doc
spaces => spaces
Testing function <function allsep_to_period_case at 0x000001F17C262310>:
snakeCase => snake.case
snake_case => snake.case
snake-case => snake.case
snake case => snake.case
snake CASE => snake.case
snake.case => snake.case
variable_10_case => variable.10.case
variable10Case => variable10.case
ɛrgo rE tHis => ɛrgo.r.e.t.his
hurry-up-joe! => hurry.up.joe!
c://my-docs/happy_Flag-Day/12.doc => c://my.docs/happy.flag.day/12.doc
spaces => spaces
Testing function <function allsep_to_slash_case at 0x000001F17C2623A0>:
snakeCase => snake/case
snake_case => snake/case
snake-case => snake/case
snake case => snake/case
snake CASE => snake//case
snake.case => snake/case
variable_10_case => variable/10/case
variable10Case => variable10/case
ɛrgo rE tHis => ɛrgo/r/e/t/his
hurry-up-joe! => hurry/up/joe!
c://my-docs/happy_Flag-Day/12.doc => c:/my/docs/happy//flag//day/12/doc
spaces => spaces
Quackery
[ $ "_ -" find 3 < ] is separator ( c --> b )
[ dup lower != ] is capital ( c --> b )
[ 2 times [ reverse trim ]
$ "" false rot
witheach
[ dup separator iff
[ 2drop true ]
else
[ over if upper
swap dip join
drop false ] ]
drop ] is camelise ( $ --> $ )
[ camelise
$ "" swap
witheach
[ dup capital if
[ dip
[ char _ join ] ]
lower join ] ] is snakify ( $ --> $ )- Output:
Testing in the shell.
/O> ' [ $ "snakeCase" ... $ "snake_case" ... $ "variable_10_case" ... $ "variable10Case" ... $ "ergo rE tHis" ... $ "hurry-up-joe!" ... $ "c://my-docs/happy_Flag-Day/12.doc" ... $ " spaces " ] ... dup ... say "To camelCase:" cr ... witheach [ do camelise say " " echo$ cr ] ... cr ... say "To snake_case:" cr ... witheach [ do snakify say " " echo$ cr ] ... To camelCase: snakeCase snakeCase variable10Case variable10Case ergoRETHis hurryUpJoe! c://myDocs/happyFlagDay/12.doc spaces To snake_case: snake_case snake_case variable10_case variable10_case ergo_r_e_t_his hurry_up_joe! c://my_docs/happy_flag_day/12.doc spaces Stack empty.
Racket
#lang racket
(define input '("snakeCase" "snake_case" "variable_10_case" "variable10Case" "ɛrgo rE tHis" "hurry-up-joe!" "c://my-docs/happy_Flag-Day/12.doc" " spaces "))
;; make '-' the canonical separator by replacing '_' and ' ' with '-'
(define (dashify s)
(regexp-replace* #px"[_ ]" s "-"))
;; replace -X with -x for any upper-case X
(define (dash-upper->dash-lower s)
(regexp-replace* #px"-[[:upper:]]" s string-downcase))
;; replace X with -x for any upper-case X
(define (upper->dash-lower s)
(regexp-replace* #px"[[:upper:]]"
s
(λ (s) (string-append "-" (string-downcase s)))))
(define (string-kebabcase s)
(upper->dash-lower (dash-upper->dash-lower (dashify s))))
(define (string-snakecase s)
;; once we have kebabcase, snakecase is easy, just change '-' to '_'
(regexp-replace* #px"-" (string-kebabcase s) "_"))
(define (string-camelcase s)
;; camel is pretty easy, too - replace dash-anything with uppercase-anything
;; note: this will change non-letters as well, so -10 becomes just 10
(regexp-replace* #px"-." (string-kebabcase s) (λ (s) (string-upcase (substring s 1 2)))))
(define (convert-case to-case case-name namelist)
(printf "Conversions to ~a:~n" case-name)
(for ([name namelist])
(printf "'~a' --> '~a'~n" name (to-case (string-trim name))))
(printf "~n"))
(convert-case string-kebabcase "kebab-case" input)
(convert-case string-snakecase "snake_case" input)
(convert-case string-camelcase "camelCase" input)
- Output:
Conversions to kebab-case: 'snakeCase' --> 'snake-case' 'snake_case' --> 'snake-case' 'variable_10_case' --> 'variable-10-case' 'variable10Case' --> 'variable10-case' 'ɛrgo rE tHis' --> 'ɛrgo-r-e-t-his' 'hurry-up-joe!' --> 'hurry-up-joe!' 'c://my-docs/happy_Flag-Day/12.doc' --> 'c://my-docs/happy-flag-day/12.doc' ' spaces ' --> 'spaces' Conversions to snake_case: 'snakeCase' --> 'snake_case' 'snake_case' --> 'snake_case' 'variable_10_case' --> 'variable_10_case' 'variable10Case' --> 'variable10_case' 'ɛrgo rE tHis' --> 'ɛrgo_r_e_t_his' 'hurry-up-joe!' --> 'hurry_up_joe!' 'c://my-docs/happy_Flag-Day/12.doc' --> 'c://my_docs/happy_flag_day/12.doc' ' spaces ' --> 'spaces' Conversions to camelCase: 'snakeCase' --> 'snakeCase' 'snake_case' --> 'snakeCase' 'variable_10_case' --> 'variable10Case' 'variable10Case' --> 'variable10Case' 'ɛrgo rE tHis' --> 'ɛrgoRETHis' 'hurry-up-joe!' --> 'hurryUpJoe!' 'c://my-docs/happy_Flag-Day/12.doc' --> 'c://myDocs/happyFlagDay/12.doc' ' spaces ' --> 'spaces'
Raku
The specs are a little vague, but taking a wild stab at it... (May be completely wrong but without any examples of expected output it is hard to judge. This is what I would expect at least...)
my @tests = qww<
snakeCase snake_case variable_10_case variable10Case "ɛrgo rE tHis"
hurry-up-joe! c://my-docs/happy_Flag-Day/12.doc " spaces "
>;
sub to_snake_case (Str $snake_case_string is copy) {
$snake_case_string.=trim;
return $snake_case_string if $snake_case_string.contains: / \s | '/' /;
$snake_case_string.=subst: / <after <:Ll>> (<:Lu>|<:digit>+) /, {'_' ~ $0.lc}, :g;
$snake_case_string.=subst: / <after <:digit>> (<:Lu>) /, {'_' ~ $0.lc}, :g;
}
sub toCamelCase (Str $CamelCaseString is copy) {
$CamelCaseString.=trim;
return $CamelCaseString if $CamelCaseString.contains: / \s | '/' /;
$CamelCaseString.=subst: / ('_') (\w) /, {$1.uc}, :g;
}
sub to-kebab-case (Str $kebab-case-string is copy) {
$kebab-case-string.=trim;
return $kebab-case-string if $kebab-case-string.contains: / \s | '/' /;
$kebab-case-string.=subst: / ('_') (\w) /, {'-' ~ $1.lc}, :g;
$kebab-case-string.=subst: / <after <:Ll>> (<:Lu>|<:digit>+) /, {'-' ~ $0.lc}, :g;
$kebab-case-string.=subst: / <after <:digit>> (<:Lu>) /, {'-' ~ $0.lc}, :g;
}
say "{' ' x 30}to_snake_case";
printf "%33s ==> %s\n", $_, .&to_snake_case for @tests;
say "\n{' ' x 30}toCamelCase";
printf "%33s ==> %s\n", $_, .&toCamelCase for @tests;
say "\n{' ' x 30}to-kabab-case";
printf "%33s ==> %s\n", $_, .&to-kebab-case for @tests;
- Output:
to_snake_case
snakeCase ==> snake_case
snake_case ==> snake_case
variable_10_case ==> variable_10_case
variable10Case ==> variable_10_case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
toCamelCase
snakeCase ==> snakeCase
snake_case ==> snakeCase
variable_10_case ==> variable10Case
variable10Case ==> variable10Case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
to-kabab-case
snakeCase ==> snake-case
snake_case ==> snake-case
variable_10_case ==> variable-10-case
variable10Case ==> variable-10-case
ɛrgo rE tHis ==> ɛrgo rE tHis
hurry-up-joe! ==> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc ==> c://my-docs/happy_Flag-Day/12.doc
spaces ==> spaces
RPL
« 1 WHILE DUP2 DUP SUB " " == REPEAT 1 + END OVER DUP SIZE WHILE DUP2 DUP SUB " " == REPEAT 1 - END SWAP DROP SUB » 'TRIM' STO « TRIM → s « "" 1 s SIZE FOR j s j DUP SUB CASE "- " OVER POS THEN DROP "_" END DUP "A" ≥ OVER "Z" ≤ AND THEN NUM 32 + CHR IF OVER DUP SIZE DUP SUB "_" ≠ THEN "_" SWAP + END END END + NEXT » » '→SNAKE' STO « TRIM → s « "" 1 CF 1 s SIZE FOR j s j DUP SUB CASE "-_ " OVER POS THEN DROP "" 1 SF END DUP "a" ≥ OVER "z" ≤ AND 1 FS?C AND THEN NUM 32 - CHR END END + NEXT » » '→CAMEL' STO « { "snakeCase" "snake_case" "variable_10_case" "variable10Case" "εrgo rE tHis" "hurry-up-joe!" "c://my-docs/happy_Flag-Day/12.doc" " spaces " } DUP 1 « →SNAKE » DOLIST SWAP 1 « →CAMEL » DOLIST » 'TASK' STO
- Output:
2: { "snake_case" "snake_case" "variable_10_case" "variable10_case" "εrgo_r_e_t_his" "hurry_up_joe!" "c://my_docs/happy_flag_day/12.doc" "spaces" }
1: { "snakeCase" "snakeCase" "variable10Case" "variable10Case" "εrgoRETHis" "hurryUpJoe!" "c://myDocs/happyFlagDay/12.doc" "spaces" }
Scala
object CamelCaseAndSnakeCase extends App {
val variableNames = List("snakeCase", "snake_case", "variable_10_case", "variable10Case",
"ergo rE tHis", "hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces ")
println(" " * 26 + "=== To snake_case ===")
variableNames.foreach { text =>
println(f"$text%34s --> ${toSnakeCase(text)}")
}
println("\n" + " " * 26 + "=== To camelCase ===")
variableNames.foreach { text =>
println(f"$text%34s --> ${toCamelCase(text)}")
}
def toSnakeCase(camel: String): String = {
val snake = new StringBuilder
camel.trim.replace(" ", "_").replace("-", "_").foreach { ch =>
if (snake.isEmpty || snake.last != '_' || ch != '_') {
if (ch.isUpper && snake.nonEmpty && snake.last != '_') snake.append('_')
snake.append(ch.toLower)
}
}
snake.toString
}
def toCamelCase(snake: String): String = {
val camel = new StringBuilder
var underscore = false
snake.trim.replace(" ", "_").replace("-", "_").foreach { ch =>
if (ch == '_') underscore = true
else if (underscore) {
camel.append(ch.toUpper)
underscore = false
} else camel.append(ch)
}
camel.toString
}
}
- Output:
=== To snake_case ===
snakeCase --> snake_case
snake_case --> snake_case
variable_10_case --> variable_10_case
variable10Case --> variable10_case
ergo rE tHis --> ergo_r_e_t_his
hurry-up-joe! --> hurry_up_joe!
c://my-docs/happy_Flag-Day/12.doc --> c://my_docs/happy_flag_day/12.doc
spaces --> spaces
=== To camelCase ===
snakeCase --> snakeCase
snake_case --> snakeCase
variable_10_case --> variable10Case
variable10Case --> variable10Case
ergo rE tHis --> ergoRETHis
hurry-up-joe! --> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc --> c://myDocs/happyFlagDay/12.doc
spaces --> spaces
V (Vlang)
fn to_camel(snake string) string {
mut camel := ''
mut underscore := false
letters := snake.trim(' ').runes()
for c in letters {
if c.str() in [' ','-','_'] {
underscore = true
} else if underscore {
camel += c.str().to_upper()
underscore = false
} else {
camel += c.str()
}
}
return camel
}
fn to_snake(camel string) string {
mut snake := ''
mut first := true
letters := camel.trim(' ').replace(' ','_').runes()
for c in letters {
if first {
snake+=c.str()
first = false
} else if !first && (c.str().is_upper() && c.bytes().len ==1 && c.bytes()[0].is_letter()) {
if snake[snake.len-1..snake.len] == '_' || snake[snake.len-1..snake.len] == '-' {
snake += c.str().to_lower()
}else {
snake += '_'+c.str().to_lower()
}
}else{
snake+=c.str()
}
}
return snake
}
const tests = ["snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "]
fn main() {
println(' === to_snake_case ===')
for word in tests {
println('${word:33} -> ${to_snake(word)}')
}
println(' === to_camel_case ===')
for word in tests {
println('${word:33} -> ${to_camel(word)}')
}
}- Output:
Same as Go entry
Wren
Well, I'm not entirely sure what I'm doing here as a result of space and hyphen being treated as equivalent to underscore but, in the case of the 'to snake' conversion:
1. I've retained any hyphens in the result string but replaced spaces with underscores as it says that white space is not permitted as part of the variable name.
2. I've assumed that an underscore should not be added if the previous character was already a separator.
import "./str" for Char
import "./fmt" for Fmt
var toCamel = Fn.new { |snake|
snake = snake.trim()
var camel = ""
var underscore = false
for (c in snake) {
if ("_- ".contains(c)) {
underscore = true
} else if (underscore) {
camel = camel + Char.upper(c)
underscore = false
} else {
camel = camel + c
}
}
return camel
}
var toSnake = Fn.new { |camel|
camel = camel.trim().replace(" ", "_") // we don't want any spaces in the result
var snake = ""
var first = true
for (c in camel) {
if (first) {
snake = snake + c
first = false
} else if (!first && Char.isUpper(c)) {
if (snake[-1] == "_" || snake[-1] == "-") {
snake = snake + Char.lower(c)
} else {
snake = snake + "_" + Char.lower(c)
}
} else {
snake = snake + c
}
}
return snake
}
var tests = [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "ɛrgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "
]
System.print(" === to_snake_case ===")
for (camel in tests) {
Fmt.print("$33s -> $s", camel, toSnake.call(camel))
}
System.print("\n === toCamelCase ===")
for (snake in tests) {
Fmt.print("$33s -> $s", snake, toCamel.call(snake))
}
- Output:
=== to_snake_case ===
snakeCase -> snake_case
snake_case -> snake_case
variable_10_case -> variable_10_case
variable10Case -> variable10_case
ɛrgo rE tHis -> ɛrgo_r_e_t_his
hurry-up-joe! -> hurry-up-joe!
c://my-docs/happy_Flag-Day/12.doc -> c://my-docs/happy_flag-day/12.doc
spaces -> spaces
=== toCamelCase ===
snakeCase -> snakeCase
snake_case -> snakeCase
variable_10_case -> variable10Case
variable10Case -> variable10Case
ɛrgo rE tHis -> ɛrgoRETHis
hurry-up-joe! -> hurryUpJoe!
c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc
spaces -> spaces
XPL0
string 0; \use zero-terminated strings
char Out(100); \output string (made global for safety)
func Trim(Str); \Trim leading and trailing spaces from string
char Str;
int I;
[while Str(0) = $20 do Str:= Str+1; \skip leading spaces
I:= 0; \skip to end of string (+1)
while Str(I) # 0 do I:= I+1;
while I>0 & Str(I-1)=$20 do I:= I-1; \skip back to first non-space
Str(I):= 0; \chop off any trailing spaces
return Str;
];
func ToSnake(In); \Convert string to snake_case
char In;
int I, J, C, UL;
[I:= 0; J:= 0; UL:= true; \suppress leading & redundant underlines
repeat C:= In(I); I:= I+1; \get character from input string
if C>=^A & C<=^Z then \convert uppercase to "_" + lowercase
[if not UL then [Out(J):= ^_; J:= J+1];
Out(J):= C+$20; J:= J+1;
UL:= false;
]
else if C=$20 or C=^- then \convert to underlines
[if not UL then [Out(J):= ^_; J:= J+1; UL:= true]
]
else [Out(J):= C; J:= J+1; UL:= C=^_];
until C = 0;
return Out;
];
func ToCamel(In); \Convert string to camelCase
char In;
int I, J, C;
[I:= 0; J:= 0;
repeat C:= In(I); I:= I+1;
if C=^_ or C=^- or C=$20 then
[C:= In(I); I:= I+1;
if C>=^a & C<=^z then C:= C-$20;
Out(J):= C; J:= J+1;
]
else [Out(J):= C; J:= J+1];
until C = 0;
return Out;
];
int Strings, I;
[Strings:= [
"snakeCase", "snake_case", "variable_10_case", "variable10Case", "\u025brgo rE tHis",
"hurry-up-joe!", "c://my-docs/happy_Flag-Day/12.doc", " spaces "];
Text(0, "To snake case:^M^J");
for I:= 0 to 7 do
[Text(0, Strings(I));
Text(0, " -> ");
Text(0, ToSnake(Trim(Strings(I))));
CrLf(0);
];
Text(0, "To camel case:^M^J");
for I:= 0 to 7 do
[Text(0, Strings(I));
Text(0, " -> ");
Text(0, ToCamel(Trim(Strings(I))));
CrLf(0);
];
]- Output:
To snake case: snakeCase -> snake_case snake_case -> snake_case variable_10_case -> variable_10_case variable10Case -> variable10_case \u025brgo rE tHis -> \u025brgo_r_e_t_his hurry-up-joe! -> hurry_up_joe! c://my-docs/happy_Flag-Day/12.doc -> c://my_docs/happy_flag_day/12.doc spaces -> spaces To camel case: snakeCase -> snakeCase snake_case -> snakeCase variable_10_case -> variable10Case variable10Case -> variable10Case \u025brgo rE tHis -> \u025brgoRETHis hurry-up-joe! -> hurryUpJoe! c://my-docs/happy_Flag-Day/12.doc -> c://myDocs/happyFlagDay/12.doc spaces -> spaces