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(Adding Haskell) |
m (→[[#ALGOL 68]]: add FOR loop version with no exception) |
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{{task|Text processing}} |
{{task|Text processing}} |
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Find the index of a string (needle) in an array of strings (haystack), or else raise an exception if the needle is missing. |
Find the index of a string (needle) in an array of strings (haystack), or else raise an exception if the needle is missing. |
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If there is more then one occurrence then return smallest i such that haystack[i] = needle. |
If there is more then one occurrence then return smallest i such that haystack[i] = needle. |
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end "+"; |
end "+"; |
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Haystack : List := "Zig"+"Zag"+" |
Haystack : List := "Zig"+"Zag"+"Wally"+"Ronald"+"Bush"+"Krusty"+"Charlie"+"Bush"+"Bozo"; |
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procedure Check (Needle : String) is |
procedure Check (Needle : String) is |
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<pre> |
<pre> |
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Washington is not in |
Washington is not in |
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Bushat |
Bushat 5 |
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</pre> |
</pre> |
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=={{header|ALGOL 68}}== |
=={{header|ALGOL 68}}== |
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===Using a FORMAT "value error" exception=== |
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FORMAT hay stack := $c("Zig","Zag"," |
FORMAT hay stack := $c("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo")$; |
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[]STRING needles = ("Washington","Bush"); |
[]STRING needles = ("Washington","Bush"); |
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<pre> |
<pre> |
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Washington is not in haystack |
Washington is not in haystack |
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5 Bush |
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</pre> |
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===Using a manual FOR loop with no exception=== |
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[]STRING hay stack = ("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"); |
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PROC index = ([]STRING hay stack, STRING needle)INT:( |
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INT index; |
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FOR i FROM LWB hay stack TO UPB hay stack DO |
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index := i; |
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IF hay stack[index] = needle THEN |
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found |
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FI |
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OD; |
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else: |
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LWB hay stack - 1 |
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EXIT |
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found: |
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index |
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); |
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[]STRING needles = ("Washington","Bush"); |
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FOR i TO UPB needles DO |
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STRING needle := needles[i]; |
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INT result = index(hay stack, needle); |
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IF result >= LWB hay stack THEN |
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printf(($d" "gl$, result, needle)) |
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ELSE |
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printf(($g" "gl$,needle, "is not in haystack")) |
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FI |
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OD |
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Output:<pre> |
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Washington is not in haystack |
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5 Bush |
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</pre> |
</pre> |
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import Data.List |
import Data.List |
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haystack=["Zig","Zag"," |
haystack=["Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"] |
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needles = ["Washington","Bush"] |
needles = ["Washington","Bush"] |
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I use 'lambda' notation for readability. |
I use 'lambda' notation for readability. |
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:Find 'just' an index: |
:Find 'just' an index: |
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*Main> map (\x -> (x,findIndex (==x) haystack)) needles |
*Main> map (\x -> (x,findIndex (==x) haystack)) needles |
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[("Washington",Nothing),("Bush",Just |
[("Washington",Nothing),("Bush",Just 4)] |
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Want to know if there are there more Bushes hiding in the haystack? |
Want to know if there are there more Bushes hiding in the haystack? |
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*Main> map (\x -> (x,findIndices (==x) haystack)) needles |
*Main> map (\x -> (x,findIndices (==x) haystack)) needles |
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[("Washington",[]),("Bush",[ |
[("Washington",[]),("Bush",[4,7])] |
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To be complete. Here is the 'point free' version of the task: |
To be complete. Here is the 'point free' version of the task: |
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import Control.Monad |
import Control.Monad |
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*Main> map (ap (,) (flip findIndex haystack . (==))) needles |
*Main> map (ap (,) (flip findIndex haystack . (==))) needles |
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[("Washington",Nothing),("Bush",Just |
[("Washington",Nothing),("Bush",Just 4)] |
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=={{header|J}}== |
=={{header|J}}== |
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J has a general and optimized lookup function, <tt>i.</tt>. For example: |
J has a general and optimized lookup function, <tt>i.</tt>. For example: |
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H =: ;:'Zig Zag Ronald |
H =: ;:'Zig Zag Wally Ronald Bush Krusty Charlie Bush Bozo' NB. Haystack |
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N =: ;:'Washington Bush' |
N =: ;:'Washington Bush' NB. Needles |
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H i. N |
H i. N |
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H ;:^:_1@(](>@{:@]|."_1(,.>@{.))i.({;(~:_1+#))1|.'is not in haystack';":&.>@i.@#@[) N |
H ;:^:_1@(](>@{:@]|."_1(,.>@{.))i.({;(~:_1+#))1|.'is not in haystack';":&.>@i.@#@[) N |
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Washington is not in haystack |
Washington is not in haystack |
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4 Bush |
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To elaborate a bit: Array-oriented languages (like J) consume the input and produce the output ''in toto''. |
To elaborate a bit: Array-oriented languages (like J) consume the input and produce the output ''in toto''. |
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import java.util.Arrays; |
import java.util.Arrays; |
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List<String> haystack = Arrays.asList("Zig","Zag"," |
List<String> haystack = Arrays.asList("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"); |
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for (String needle : new String[]{"Washington","Bush"}) { |
for (String needle : new String[]{"Washington","Bush"}) { |
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for arrays, you have to do it manually: |
for arrays, you have to do it manually: |
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<java>String[] haystack = {"Zig","Zag"," |
<java>String[] haystack = {"Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"}; |
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OUTERLOOP: |
OUTERLOOP: |
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=={{header|Python}}== |
=={{header|Python}}== |
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<python> |
<python> |
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haystack=["Zig","Zag"," |
haystack=["Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"] |
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for needle in ("Washington","Bush"): |
for needle in ("Washington","Bush"): |
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