Perl split Function
last modified April 4, 2025
The Perl split function divides strings into substrings using
a delimiter. It returns a list of these substrings, which can be assigned
to an array.
split is powerful for parsing text data, with options to
control splitting behavior. It can use fixed strings or regular expressions
as delimiters.
Basic split Usage
The simplest form splits on whitespace by default when no pattern is given.
#!/usr/bin/perl
use strict;
use warnings;
use v5.34.0;
my $text = "apple banana cherry";
my @fruits = split ' ', $text;
print "Fruits:\n";
foreach my $fruit (@fruits) {
print "- $fruit\n";
}
This splits the string on whitespace into an array. Each word becomes an element in the resulting array.
$ ./basic.pl Fruits: - apple - banana - cherry
Splitting on Specific Character
You can specify any single character as the delimiter for splitting.
#!/usr/bin/perl
use strict;
use warnings;
use v5.34.0;
my $csv = "John,Doe,35,New York";
my @fields = split ',', $csv;
print "Fields:\n";
for my $i (0..$#fields) {
print "$i: $fields[$i]\n";
}
This splits a CSV string on commas. Each field becomes a separate array element, which we access by index.
$ ./delimiter.pl Fields: 0: John 1: Doe 2: 35 3: New York
Limiting Number of Splits
The third parameter controls how many splits to perform.
#!/usr/bin/perl
use strict;
use warnings;
use v5.34.0;
my $path = "/usr/local/bin/perl";
my @parts = split '/', $path, 3;
print "Path components:\n";
foreach my $part (@parts) {
print "'$part'\n";
}
Here we split a path string but limit to 3 parts. The remaining delimiters are kept in the last element.
$ ./limit.pl Path components: '' 'usr' 'local/bin/perl'
Splitting on Regular Expression
split can use regex patterns for more complex splitting.
#!/usr/bin/perl
use strict;
use warnings;
use v5.34.0;
my $text = "apple,banana;cherry|date";
my @fruits = split /[,;|]/, $text;
print "Fruits:\n";
print join("\n", @fruits), "\n";
This splits on any of several delimiter characters using a character class. The regex matches comma, semicolon, or pipe.
$ ./regex.pl Fruits: apple banana cherry date
Splitting with Capture Groups
When using regex with capture groups, the captured text is included in output.
#!/usr/bin/perl
use strict;
use warnings;
use v5.34.0;
my $text = "appleXbananaYcherry";
my @parts = split /([XY])/, $text;
print "Parts:\n";
print join("|", @parts), "\n";
The delimiters themselves (X and Y) are included in the output array because they're captured. This behavior is useful when you need to preserve delimiters.
$ ./capture.pl Parts: apple|X|banana|Y|cherry
Splitting Empty Fields
By default, split discards trailing empty fields.
#!/usr/bin/perl use strict; use warnings; use v5.34.0; my $text = "one,,three,,"; my @default = split ',', $text; my @keep_all = split ',', $text, -1; print "Default split: ", scalar @default, " elements\n"; print "Keep empty: ", scalar @keep_all, " elements\n";
Using -1 as the limit preserves all trailing empty fields. The default behavior removes them from the end of the array.
$ ./empty.pl Default split: 3 elements Keep empty: 5 elements
Splitting into Variables
You can assign split results directly to variables using list context.
#!/usr/bin/perl use strict; use warnings; use v5.34.0; my $date = "2025-04-04"; my ($year, $month, $day) = split '-', $date; print "Year: $year\n"; print "Month: $month\n"; print "Day: $day\n";
This splits a date string and assigns each component to separate variables. The number of variables must match the split results.
$ ./assign.pl Year: 2025 Month: 04 Day: 04
Best Practices
- Always check results: Split might return unexpected empty lists.
- Precompile regex: For performance with repeated splits.
- Consider alternatives: For CSV, use Text::CSV module.
- Document complex splits: Regex patterns can be obscure.
Source
This tutorial covered Perl's split function with practical
examples demonstrating its usage in common scenarios.
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