How can I split a string into fixed-length parts, rather than on delimiters?

ruyler has asked for the wisdom of the Perl Monks concerning the following question: ⭐ (strings)

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Re: How can I split a string into fixed-length parts, rather than on delimiters?⭐ by Kanji (Parson) on Jul 12, 2002 at 02:37 UTC
`unpack` is arguably more appropriate than a regex: `my $fname = '41084109.udp'; my( $v1, $v2 ) = unpack( 'a4 a4', $fname );` [download]	[reply] [d/l]
Re: How can I split a string into fixed-length parts, rather than on delimiters? by jdporter (Paladin) on Apr 07, 2021 at 00:33 UTC
You can combine two nifty (i.e. rarely used) tricks: `sub fixed_width_records($$) { my( $size, $string ) = @_; open my $f, '<', \$string or die; # read from a string as if it were + a file local $/ = \$size; # "records" will be this many chars, rather than +to some end-of-line thing <$f> # parse! (i.e. read) and return the list of "records" } my( $first, $second ) = fixed_width_records( 4, "41084109.udp" ); print ">$first\n>$second\n";` [download]	[reply] [d/l]
Re: How can I split a string into fixed-length parts, rather than on delimiters? by almut (Canon) on Nov 08, 2006 at 19:42 UTC
Simply use `m//g`: `my $fname = '41084109.udp'; @filename_parts = $fname =~ /(.{1,4})/g;` [download]	[reply] [d/l] [select]
Re: How can I SPLIT a file name w/out delimiters ie: 41084109 by ackohno (Scribe) on Jul 12, 2002 at 03:31 UTC
One way would be to do something like this: `open(FILE,'41084109.udp'); $/=\4; $a = <FILE>; $b = <FILE>;` [download] The `$/` variable determines how much to read in. In this case its set to 4, to read in 4 bytes (its default value is "\n"). This might be more useful if you need more than two sets of four numbers, for something like: `open(FILE,'41084109.udp'); $/=\4; while(<FILE>) { #count the occuarnce of the 4 digits $count{$_}++; }` [download] {QA Editors note: The original question's subject line was somewhat ambiguous as to whether the person asking was trying to split a file, or a filename. The followup text was still somewhat unclear, but the example shown by the original poster clarified that he was trying to split a filename. This response will aid in splitting the contents of a file, which is different but worthy of mention.} Originally posted as a Categorized Answer.	[reply] [d/l] [select]
Re: How can I SPLIT a file name w/out delimiters ie: 41084109 by pemungkah (Priest) on Nov 08, 2006 at 01:37 UTC
Yet another way, using the fact that if you put parens around the `split()` argument, it's kept in the output instead of discarded: `@parts = split /(.{4})/, '41084109.udp';` [download] After this runs, `print "@parts"` will give you `4108 4109 .udp` [download] Obviously, if the filename isn't exactly 8.4, you'll get the wrong answer, but it's an interesting use of `split()`.	[reply] [d/l] [select]
Re: Answer: How can I SPLIT a file name w/out delimiters ie: 41084109 by ikegami (Patriarch) on Nov 08, 2006 at 03:08 UTC
Sounds like an overly complicated way of doing `@parts = '41084109.udp' =~ /(.{4})/g;` [download]	[reply] [d/l]