Perl:Find Position

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You can use the index finction to find the position of a string within a string.

Find first occurrence

Use index($s,$t) to find where $t occurs in $s.

   $s             index($s,"t")

One two three        4
four five six        -1

index($s,"t") gives the character position of the first "t" in $s.

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Find last occurrence

Use rindex($s,$t) to find the last place where $t occurs in $s.

   $s             index($s,"t")

One two three        8
four five six        -1

rindex($s,"t") gives the character position of the last "t".


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Find occurrence after ...

Use index($s,$t,$n) to find where $t occurs in $s after $n.

  $s             index($s,"t",5)

One two three        8
four five six        -1

rindex($s,"t",5) gives the character position of the first "t" after position 5.


0 1 2 3 4 5 6 7 8 9 10 11 12
O n e t w o t h r e e
f o u r f i v e s i x



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