Comma quibbling: Difference between revisions
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=={{header|Rust}}==
{{incomplete|Rust|output for no input words missing.}}
<lang Rust>
fn quibble(seq: &[~str]) -> ~str {
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Revision as of 16:42, 6 October 2013
Comma quibbling is a task originally set by Eric Lippert in his blog.
The task is to write a function to generate a string output which is the concatenation of input words from a list/sequence where:
- An input of no words produces the output string of just the two brace characters "{}".
- An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
- An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
- An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
- [] # (No input words).
- ["ABC"]
- ["ABC", "DEF"]
- ["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
D
<lang d>import std.stdio, std.string;
string quibbler(in string[] seq) pure /*nothrow*/ {
if (seq.length <= 1) return format("{%-(%s, %)}", seq); else return format("{%-(%s, %) and %s}", seq[0 .. $-1], seq[$-1]);
}
void main() {
//foreach (immutable test; [[], foreach (const test; [[], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]]) test.quibbler.writeln;
}</lang>
- Output:
{} {ABC} {ABC and DEF} {ABC, DEF, G and H}
F#
<lang fsharp>let quibble list =
let rec inner = function | [] -> "" | [x] -> x | [x;y] -> sprintf "%s and %s" x y | h::t -> sprintf "%s, %s" h (inner t) sprintf "{%s}" (inner list)
// test interactively quibble [] quibble ["ABC"] quibble ["ABC"; "DEF"] quibble ["ABC"; "DEF"; "G"] quibble ["ABC"; "DEF"; "G"; "H"] </lang>
Perl 6
<lang perl6>sub comma-quibbling(@A) {
"\{$_\}" given @A < 3 ?? @A.join(' and ') !! @A[0..*-2].join(',') ~ ' and ' ~ @A[*-1]
}
say comma-quibbling($_) for ((), (<ABC>,), (<ABC DEF>), (<ABC DEF G H>)).tree;</lang>
- Output:
{} {ABC} {ABC and DEF} {ABC,DEF,G and H}
Python
<lang python>>>> def strcat(sequence): # replace(..) can only replace the first X occurrences not the last # Hence the replace is done on the reverse of the intermediate string # then reversed back. return '{%s}' % ', '.join(sequence)[::-1].replace(',', 'dna ', 1)[::-1]
>>> for seq in ([], ["ABC"], ["ABC", "DEF"], ["ABC", "DEF", "G", "H"]): print('Input: %-24r -> Output: %r' % (seq, strcat(seq)))
Input: [] -> Output: '{}'
Input: ['ABC'] -> Output: '{ABC}'
Input: ['ABC', 'DEF'] -> Output: '{ABC and DEF}'
Input: ['ABC', 'DEF', 'G', 'H'] -> Output: '{ABC, DEF, G and H}'
>>> </lang>
Rexx
<lang Rexx> say quibbling('ABC') say quibbling('ABC DEF') say quibbling('ABC DEF G H') exit
quibbling: procedure
parse arg list if words(list) < 2 then return list return translate(strip(subword(list,1,words(list)-1)),',',' ') 'and' word(list,words(list))
</lang>
- Output:
{ABC} {ABC and DEF} {ABC,DEF,G and H}
Rust
<lang Rust> fn quibble(seq: &[~str]) -> ~str {
match seq { [] => ~"{}", [ref w] => fmt!("{%s}", *w), [..ws, ref w] => fmt!("{%s and %s}", ws.connect(", "), *w), }
}
fn main() {
println(quibble([~"ABC"])); println(quibble([~"ABC", ~"DEF"])); println(quibble([~"ABC", ~"DEF", ~"G", ~"H"]));
} </lang>
- Output:
{ABC} {ABC and DEF} {ABC, DEF, G and H}