Perl - Why I can't use a variable into regex?
Why can't I use if($l =~ $ARGV[0]) but I can use if($l =~ /$ARGV[0]/g?
first case
$ perl script.pl '/^[w]/g'
second case
$ perl script.pl '^[w]'
perl
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
add a comment |
Why can't I use if($l =~ $ARGV[0]) but I can use if($l =~ /$ARGV[0]/g?
first case
$ perl script.pl '/^[w]/g'
second case
$ perl script.pl '^[w]'
perl
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
add a comment |
Why can't I use if($l =~ $ARGV[0]) but I can use if($l =~ /$ARGV[0]/g?
first case
$ perl script.pl '/^[w]/g'
second case
$ perl script.pl '^[w]'
perl
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
Why can't I use if($l =~ $ARGV[0]) but I can use if($l =~ /$ARGV[0]/g?
first case
$ perl script.pl '/^[w]/g'
second case
$ perl script.pl '^[w]'
perl
perl
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
edited 17 mins ago
Rui F Ribeiro
40.1k1479136
40.1k1479136
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
asked Dec 13 '15 at 16:50
The dudeThe dude
1259
1259
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$ARGV[0] is a scalar string. When you do if($l =~ $ARGV[0]) and $ARGV[0] is '/^[w]/g' this is equivalent to if($l =~ '/^[w]/g') instead of if($l =~ /^[w]/g). In the former case the slashes are simply characters in a string while in the later they are a part of the Perl syntax that delimits a regular expression.
answered Dec 13 '15 at 17:26
nwknwk
663513
2
To work around this, you can use$regex = qr{$ARGV [0]}
– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
add a comment |
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1 Answer
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1 Answer
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votes
$ARGV[0] is a scalar string. When you do if($l =~ $ARGV[0]) and $ARGV[0] is '/^[w]/g' this is equivalent to if($l =~ '/^[w]/g') instead of if($l =~ /^[w]/g). In the former case the slashes are simply characters in a string while in the later they are a part of the Perl syntax that delimits a regular expression.
answered Dec 13 '15 at 17:26
nwknwk
663513
2
To work around this, you can use$regex = qr{$ARGV [0]}
– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
add a comment |
$ARGV[0] is a scalar string. When you do if($l =~ $ARGV[0]) and $ARGV[0] is '/^[w]/g' this is equivalent to if($l =~ '/^[w]/g') instead of if($l =~ /^[w]/g). In the former case the slashes are simply characters in a string while in the later they are a part of the Perl syntax that delimits a regular expression.
answered Dec 13 '15 at 17:26
nwknwk
663513
2
To work around this, you can use$regex = qr{$ARGV [0]}
– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
add a comment |
$ARGV[0] is a scalar string. When you do if($l =~ $ARGV[0]) and $ARGV[0] is '/^[w]/g' this is equivalent to if($l =~ '/^[w]/g') instead of if($l =~ /^[w]/g). In the former case the slashes are simply characters in a string while in the later they are a part of the Perl syntax that delimits a regular expression.
answered Dec 13 '15 at 17:26
nwknwk
663513
$ARGV[0] is a scalar string. When you do if($l =~ $ARGV[0]) and $ARGV[0] is '/^[w]/g' this is equivalent to if($l =~ '/^[w]/g') instead of if($l =~ /^[w]/g). In the former case the slashes are simply characters in a string while in the later they are a part of the Perl syntax that delimits a regular expression.
answered Dec 13 '15 at 17:26
nwknwk
663513
edited Dec 13 '15 at 17:34
answered Dec 13 '15 at 17:26
nwknwk
663513
answered Dec 13 '15 at 17:26
nwknwk
663513
answered Dec 13 '15 at 17:26
nwknwk
663513
663513
2
To work around this, you can use$regex = qr{$ARGV [0]}
– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
add a comment |
2
To work around this, you can use$regex = qr{$ARGV [0]}
– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
2
2
To work around this, you can use
$regex = qr{$ARGV [0]}– Joseph R.
Dec 13 '15 at 20:03
To work around this, you can use
$regex = qr{$ARGV [0]}– Joseph R.
Dec 13 '15 at 20:03
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
Hey, thanks for the advice guys. Could you take a look at this question mentioning other error in the same script? unix.stackexchange.com/questions/249368/…
– The dude
Dec 14 '15 at 21:08
add a comment |
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