RaineyM
asked on
Regular Expression Help
I am retrieving the following string from a MySQL database and need a regular expression to detect the [code]...[/code] parts. No matter what expression I use, it won't detect it.
This is a test.\n[code]\n<p>Hello</p
This is a test.\n[code]\n<p>Hello</p
ASKER CERTIFIED SOLUTION
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my($Test) = "\n[code]\n<p>Hello</p>\n<
my(@Parts) = undef;
while ($Test =~ m!\[code\](.*?)\[/code\]!g
{
push @Parts, $1;
};
print "There are ", scalar $#Parts, " parts detected...\n";
foreach (@Parts)
{
print "\n$_";
};
my(@Parts) = undef;
while ($Test =~ m!\[code\](.*?)\[/code\]!g
{
push @Parts, $1;
};
print "There are ", scalar $#Parts, " parts detected...\n";
foreach (@Parts)
{
print "\n$_";
};
Raineym,
the important thing in all these solutions is the use of /s
s - enables multiline match
Manav
the important thing in all these solutions is the use of /s
s - enables multiline match
Manav
ASKER
Thank you Manav.
I can't believe I forgot /s. Doh!
I can't believe I forgot /s. Doh!
Happens ;)
Manav
Manav
ASKER
Ok, now when there is more than one [code]...[/code] in the string, it detects everything between the first occurance of [code] and the last occurance of [/code].
No no
then use
use strict;
use warnings;
my $var="This is a test.\n[code]\n<p>Hello</p
while ($var =~ m/\[code\](.*?)\[\/code\]/
print "detected" ;
print "$1" ;
}
Notice the .*? instead of the .* in the regex.
A regex by default matches the largest string it can find. a ? before the regex overrides this default behaviour.
In your problem, hence you wnat to match the smallest string between two [code] and [\code]. Hence this will work
also remember to put the g(for global match).
Manav
then use
use strict;
use warnings;
my $var="This is a test.\n[code]\n<p>Hello</p
while ($var =~ m/\[code\](.*?)\[\/code\]/
print "detected" ;
print "$1" ;
}
Notice the .*? instead of the .* in the regex.
A regex by default matches the largest string it can find. a ? before the regex overrides this default behaviour.
In your problem, hence you wnat to match the smallest string between two [code] and [\code]. Hence this will work
also remember to put the g(for global match).
Manav
And if you want to have [code] and [\code] in $1 too, use
use strict;
use warnings;
my $var="This is a test.\n[code]\n<p>Hello</p
while ($var =~ m/(\[code\].*?\[\/code\])/
print "detected\n" ;
print "$1" ;
}
Manav
use strict;
use warnings;
my $var="This is a test.\n[code]\n<p>Hello</p
while ($var =~ m/(\[code\].*?\[\/code\])/
print "detected\n" ;
print "$1" ;
}
Manav
ASKER
That I did no know. ** Gray Matter Expanding **
Any way to give bonus points? You deserve it.
Any way to give bonus points? You deserve it.
Raineym,
You could put a request to community support. Or post another dummy question, then I can post a stupid answer to the dummy question and you award me the points. ;)
Actually, most of the ppl dont know this maximum matching property of regex. Hence, most of them dont know the use of a ? (apart from when used after a metacharacter)
.? -> matches 0 or 1 character
.*? -> matches the minimum number of any characters. This by itslef dosnt make much if a sense unless it is surronded by ohter fragments of regex on either side or both sides.
Manav
You could put a request to community support. Or post another dummy question, then I can post a stupid answer to the dummy question and you award me the points. ;)
Actually, most of the ppl dont know this maximum matching property of regex. Hence, most of them dont know the use of a ? (apart from when used after a metacharacter)
.? -> matches 0 or 1 character
.*? -> matches the minimum number of any characters. This by itslef dosnt make much if a sense unless it is surronded by ohter fragments of regex on either side or both sides.
Manav
ASKER
OK, look for the question "What is the maximum matching property of regex?".
use strict;
use warnings;
my $var="This is a test.\n[code]\n<p>Hello</p
$var =~ s/^.*(\[code\].*\[\/code\]
print $var
Manav