use strict;
my $str = 'import pandas, os, sys';
my $regex = qr/\s*
(?:
(?:^from\s+
( # Base (from (base) import ...)
(?:[a-zA-Z_][a-zA-Z_0-9]* # Variable name
(?:\.[a-zA-Z_][a-zA-Z_0-9]*)* # Attribute (.attr)
)
)\s+import\s+
)
|
(?:^import\s|,)\s*
)
( # Name of imported module (import (this))
(?:[a-zA-Z_][a-zA-Z_0-9]* # Variable name
(?:\.[a-zA-Z_][a-zA-Z_0-9]*)* # Attribute (.attr)
)
)
(?:
\s+as\s+
( # Variable module is imported into (import foo as bar)
(?:[a-zA-Z_][a-zA-Z_0-9]* # Variable name
(?:\.[a-zA-Z_][a-zA-Z_0-9]*)* # Attribute (.attr)
)
)
)?
\s*
(?=,|$) # Ensure there is another thing being imported or it is the end of string/mxp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html