I want to split a string with multiple patterns:
ex.
my $string= "10:10:10, 12/1/2011";
my @string = split(/firstpattern/secondpattern/thirdpattern/, $string);
foreach(@string) {
print "$_\n";
}
I want to have an output of:
10
10
10
12
1
2011
What is the proper way to do this?
Use a character class in the regex delimiter to match on a set of possible delimiters.
my $string= "10:10:10, 12/1/2011";
my @string = split /[:,\s\/]+/, $string;
foreach(@string) {
print "$_\n";
}
Explanation
The pair of slashes /.../ denotes the regular expression or pattern to be matched.
The pair of square brackets [...] denotes the character class of the regex.
Inside is the set of possible characters that can be matched: colons :, commas ,, any type of space character \s, and forward slashes \/ (with the backslash as an escape character).
The + is needed to match on 1 or more of the character immediately preceding it, which is the entire character class in this case. Without this, the comma-space would be considered as 2 separate delimiters, giving you an additional empty string in the result.
Wrong tool!
my $string = "10:10:10, 12/1/2011";
my @fields = $string =~ /([0-9]+)/g;
You can split on non-digits;
#!/usr/bin/perl
use strict;
use warnings;
use 5.014;
my $string= "10:10:10, 12/1/2011";
say for split /\D+/, $string;
my $string= "10:10:10, 12/1/2011";
my @string = split(m[(?:firstpattern|secondpattern|thirdpattern)+], $string);
my @string = split(m[(?:/| |,|:)+], $string);
print join "\n", @string;
/| |,|: better written as [/ ,:]
perl -wE "use Benchmark qw(cmpthese); $a=qq(10:10:10, 12/1/2011); cmpthese(100000, { Piped => sub { my @r = split (m[(?:/| |,|:)+], $a); }, Class => sub { my @r = split (m[(?:[/ ,:])+], $a); } });" Piped 142450/s -- -27% // Class 194175/s 36% -- Looks like character class is 36% faster.m##, the results go up to 45% faster.
To answer your original question:
you were looking for the | operator:
my $string = "10:10:10, 12/1/2011";
my @string = split(/:|,\s*|\//, $string);
foreach(@string) {
print "$_\n";
}
But, as the other answers point out, you can often improve on that with further simplifications or generalizations.
If numbers are what you want, extract numbers:
my @numbers = $string =~ /\d+/g;
say for @numbers;
Capturing parentheses are not required, as specified in perlop:
The /g modifier specifies global pattern matching--that is, matching as many times as possible within the string. How it behaves depends on the context. In list context, it returns a list of the substrings matched by any capturing parentheses in the regular expression. If there are no parentheses, it returns a list of all the matched strings, as if there were parentheses around the whole pattern.
split is a very nice tool, but works best with uniform delimiters, I feel. In this case, the common element is numbers, so it's easier to work with them.As you're parsing something that is rather obviously a date/time, I wonder if it would make more sense to use DateTime::Format::Strptime to parse it into a DateTime object.
