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How can I split a string into chunks of size n bytes?

by tadman (Prior)
on Apr 23, 2001 at 22:24 UTC ( #74815=categorized question: print w/replies, xml ) Need Help??
Contributed by tadman on Apr 23, 2001 at 22:24 UTC
Q&A  > strings


Description:

As in:     @bits = chunk($scalar, $bytes);
Which would return $scalar in @bits, each $bytes size, plus the remainder in the last entry.

Answer: How can I split a string into chunks of size n bytes?
contributed by Masem

@bits = ( $scalar =~ /.{1,$bytes}/gs );

Edited by tye to add "s" on the end otherwise "." won't match newlines.

Edited by chipmunk to change {0,$bytes} to {1,$bytes}; otherwise a null string is matched at the end.

Answer: How can I split a string into chunks of size n bytes?
contributed by MeowChow

push @bits, substr $scalar, 0, $bytes, '' while length $scalar;
Answer: How can I split a string into chunks of size n bytes?
contributed by davido

If by "bytes" you mean ASCII characters from a string, this is a simple and relatively fast solution:

my $string = "1234567890abcdefghijABCDEFGHIJK"; my $n = 2; # $n is group size. my @groups = unpack "a$n" x (length( $string ) /$n ), $string;

This solution has a couple of nice bonuses. First, it will only return complete groups. If you have extra characters that don't complete out a group, it won't give them to you. Second, it is easily adaptable to any other data type that pack and unpack support.

UPDATE: As Aristotle pointed out here, if you want the last group even if it's incomplete you may do this:

my @groups = unpack "a$n" x ((length($string)/$n)-1) . "a*", $string;

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