$string =~ /$pattern/i

[cracraft]

Hi,

I am attempting to find out if a $string contains $pattern.

$string =~ /$pattern/i

normally solves it.

However, I noticed that if $pattern contains something like

(4)

and $string contains something like

ABC(4)

then

$string =~ /$pattern/i

does not work, because of the parenthesis.

I want a flat-out literal match where $string can contain any
occurrence of $pattern regardless of parenthesis.

In other words, I don't want the special characters of regular
expressions interpreted.

I could write my own pattern matcher but resist it and would
think Perl could provide the above feature.

Anybody?

--Stuart

 

[Gunnar Hjalmarsson]

I am attempting to find out if a $string contains $pattern.

$string =~ /$pattern/i

normally solves it.

However, I noticed that if $pattern contains something like

(4)

and $string contains something like

ABC(4)

then

$string =~ /$pattern/i

does not work, because of the parenthesis.

I want a flat-out literal match where $string can contain any
occurrence of $pattern regardless of parenthesis.

In other words, I don't want the special characters of regular
expressions interpreted.

$string =~ /\Q$pattern/i

I could write my own pattern matcher

Really? And still not able to solve this problem?

 

[Paul Lalli]

I want a flat-out literal match where $string can contain any
occurrence of $pattern regardless of parenthesis.

perldoc -f index

In other words, I don't want the special characters of regular
expressions interpreted.

perldoc -f quotemeta


Paul Lalli

 

[Tad McClellan]

Quote meta doesen't work for everything.

Yes it does.

 

[xhoster]

Yes it does.

I tried to weed my garden with it, and I'm not getting anywhere.

Xho

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[Peter J. Holzer]

I don't know what version of Perl you use but in my Perl 5.6.1 quotemeta
sometime return curious results ;-)

print quotemeta('This is a string');

By me the space (0x20h) is not need to escape.

The space must be escaped if used in a regexp with the /x modifier.
And escaping doesn't hurt otherwise, so this is not an example where
quotemeta "doesn't work".

hp

 

[Tad McClellan]

I don't know what version of Perl you use

That's OK, as it is not relevant.

but in my Perl 5.6.1 quotemeta
sometime return curious results ;-)

print quotemeta('This is a string');

By me the space (0x20h) is not need to escape.

Errr, then don't call quotemeta on it!

 

[Tad McClellan]

Errr, then don't call quotemeta on it!

This was be an example. In real script I mean something like
my $variable = myfunction(quotemeta($ARGV[0]));

where myfunction() need to get escaped string as parameter but escaped space
is nonsese.
Now I realise it as
my $arg = quotemeta($ARGV[0]);
$arg =~ s/\\\x20/ /g;
my $variable = myfunction($arg);

Know you better way?

Sure. The first sentence of its documentation says:

Returns the value of EXPR with all non-"word" characters backslashed.

If you want all non-"word" characters except space backslashed,
then write a s/// that does that instead:

$arg =~ s/([^\w ])/\\$1/g;