Re: Applying a regular expression to a string

in reply to Applying a regular expression to a string

Try something like:

my $message_id = $1 if $message =~ m/([\w\d]+)\s+.*/;
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Comment on Re: Applying a regular expression to a string Download Code

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Re^2: Applying a regular expression to a string by Smylers (Pilgrim) on Apr 04, 2005 at 13:22 UTC
`my $message_id = $1 if $message =~ m/([\w\d]+)\s+./;` Putting `my` (a compile-time directive) with an `if` statement modifier (which can only take place at run-time) is confusing, and therefore deprecated. Also, there's no point at all in having `.` at the end of the regexp: since one of the things it would happily match is nothing, it isn't making any restrictions at all about what can follow the `\s+`, so is just adding noise. Finally, the `\w` class already includes digits, so writing `[\w\d]` doesn't add anything. Here's how I might have written this: `$message =~ /^(\w+)/ or die "Message '$message' doesn't start with an identifier.\n"; my $message_id = $1;` [download] `die` might not be the most appropriate thing to do here; adjust as appropriate. But if you're adamant that `$message` could never not match the pattern, then a `die` test is better than nothing: if you're right, then it'll never happen, and if you're wrong then your assumption was wrong so there's a problem elsewhere and at least you found out about it. Smylers	[reply] [d/l] [select]

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Re^2: Applying a regular expression to a string
by Smylers (Pilgrim) on Apr 04, 2005 at 13:22 UTC

my $message_id = $1 if $message =~ m/([\w\d]+)\s+.*/;

Putting my (a compile-time directive) with an if statement modifier (which can only take place at run-time) is confusing, and therefore deprecated.

Also, there's no point at all in having .* at the end of the regexp: since one of the things it would happily match is nothing, it isn't making any restrictions at all about what can follow the \s+, so is just adding noise.

Finally, the \w class already includes digits, so writing [\w\d] doesn't add anything.

Here's how I might have written this:

$message =~ /^(\w+)/
    or die "Message '$message' doesn't start with an identifier.\n";
my $message_id = $1;
[download]

die might not be the most appropriate thing to do here; adjust as appropriate. But if you're adamant that $message could never not match the pattern, then a die test is better than nothing: if you're right, then it'll never happen, and if you're wrong then your assumption was wrong so there's a problem elsewhere and at least you found out about it.

Smylers

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