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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. If there is more then one occurrence then return smallest i such that haystack[i] = needle.

ALGOL 68

With FORMAT value error exception

FORMAT haystack := $c("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo")$;

[]STRING needles = ("Washington","Bush");

FILE needle exception; STRING ref needle;
associate(needle exception, ref needle);

PROC index = (FORMAT haystack, REF STRING needle)INT:(
  INT out;
  ref needle := needle;
  getf(needle exception,(haystack, out));
  out
);

FOR i TO UPB needles DO
  STRING needle := needles[i];
  on value error(needle exception, (REF FILE f)BOOL: value error);
    printf(($d" "gl$,index(haystack, needle), needle));
    end on value error;
  value error:
    printf(($g" "gl$,needle, "is not in haystack"));
  end on value error: reset(needle exception)
OD

Output:

Washington is not in haystack
4 Bush

Manual FOR loop - no exception

[]STRING haystack = ("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo");

PROC index = ([]STRING haystack, STRING needle)INT:(
  INT index;
  FOR i FROM LWB haystack TO UPB haystack DO
    index := i;
    IF haystack[index] = needle THEN found FI
  OD;
    LWB haystack - 1 # not found #
  EXIT
  found: index
);

[]STRING needles = ("Washington","Bush");
FOR i TO UPB needles DO
  STRING needle := needles[i];
  INT result = index(haystack, needle);
  IF result >= LWB haystack THEN
    printf(($d" "gl$, result, needle))
  ELSE
    printf(($g" "gl$,needle, "is not in haystack"))
  FI
OD

Output:

Washington is not in haystack
5 Bush

Java

for Lists, they have an indexOf() method: <java>import java.util.List; import java.util.Arrays;

List<String> haystack = Arrays.asList("Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo");

for (String needle : new String[]{"Washington","Bush"}) {

   int index = haystack.indexOf(needle);
   if (index < 0)
       System.out.println(needle + " is not in haystack");
   else
       System.out.println(index + " " + needle);

}</java>

for arrays, you have to do it manually: <java>String[] haystack = {"Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"};

OUTERLOOP: for (String needle : new String[]{"Washington","Bush"}) {

   for (int i = 0; i < haystack.length; i++)
       if (needle.equals(haystack[i])) {
           System.out.println(i + " " + needle);
           continue OUTERLOOP;
       }
   System.out.println(needle + " is not in haystack");

}</java> Output:

Washington is not in haystack
4 Bush

Python

<python> haystack=["Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"]

for needle in ("Washington","Bush"):

 try:
   print haystack.index(needle), needle
 except ValueError, value_error:
   print needle,"is not in haystack"

</python> Output:

Washington is not in haystack
4 Bush