Removing data from a string with Regex

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Re: Removing data from a string with Regex by jwest (Friar) on Nov 15, 2001 at 02:14 UTC
Instead of using substitution, you might try something like this: `$from =~ /^([^@]+)@/; $from = $1;` [download] The first line will take all the characters starting from the beginning of $from that aren't '@' and capture them to the special variable $1. Then, reassign $from to the value of $1. To do this with substitution, you could try: `$from =~ s/@.*//;` [download] which would substitute the '@' and anything that followed with nothing. Hope this helps! --jwest -><- -><- -><- -><- -><- All things are Perfect To every last Flaw And bound in accord With Eris's Law - HBT; The Book of Advice, 1:7	[reply] [d/l] [select]
Re: Re: Removing data from a string with Regex by pike (Monk) on Nov 15, 2001 at 13:46 UTC
Taking this approach one step further, the original loop could be simplified to: `while (<FILE>) { my ($name) = /^--from\s*([^@]+)/; print ($name) if defined $name; }` [download] pike	[reply] [d/l]
Re: Re: Re: Removing data from a string with Regex by CharlesClarkson (Curate) on Nov 15, 2001 at 23:01 UTC
That regex would allow `--from @something.com` to pass and assign ' ' to `$name`. It would likely be better to use:`/^--from\s([^@\s]+)/` which fails for `--from @something.com` and could simplify the code further. `while ( <FILE> ) { print $1 if /^--from\s([^@\s]+)/; } or: print $1 if /^--from\s*([^@\s]+)/ while <FILE>;` [download] HTH, Charles K. Clarkson	[reply] [d/l] [select]
Re: Removing data from a string with Regex by c (Hermit) on Nov 15, 2001 at 02:16 UTC
you may want to look at this to look over the basics of regular expressions. basically, i think you're wanting to match everything after the @. so you may want to look through perlre and look for what matches any single character and how to match it one or more times. the other option, you might want to take on this one is splitting the string based on the @ and grabbing the first instance within the split. something like `$from = (split(/\@/, $from))[0];` humbly -c	[reply] [d/l]
Re: Removing data from a string with Regex by jclovs (Sexton) on Nov 15, 2001 at 02:29 UTC
In true TMTOWTDI style you could also use that which is below, although it is lacking a bit in the optimization. $from =~ /@/; $from = $`; [download] jclovs	[reply] [d/l]
Re: Removing data from a string with Regex by s0ttle (Scribe) on Nov 15, 2001 at 02:52 UTC
You have a common precedence issue. Change the following line. `open FILE, $filename \|\| die $!;` [download] to `open FILE, $filename or die $!;` [download] or if you really want to use \|\| `open(FILE,$filename) \|\| die $!;` [download] also it wouldn't hurt to be more verbose: `die "Could not open $filename: $!\n";` [download] UPDATE: The usage of the \g modifier is for multiple matching,substituting,etc. you don't need it if you know what you are searching for only occurs once as is the case: The original value of $from is "--from me@mydomain.com \" EXAMPLE: `$str ='abcd'; $str =~s/a//g; # \g unnecessary ## $str = 'abacad'; $str =~s/a//g; # more appropriate` [download] It wouldn't hurt to also have a look at perlop -tengo mas que aprender	[reply] [d/l] [select]
Re: Removing data from a string with Regex by scain (Curate) on Nov 15, 2001 at 02:13 UTC
What you need is `$from =~ s/@.+//g;`; the ".+" matches everything from @ to the end of the string. Scott Minor update: Just to be clear, this is probably not the best way to do this, it just happens to work. Specifically, the .+ matches upto but not including the line feed that is at the end of the string, since it came along to $from from $_. In general, you would probably want to chomp $_ and then explicitly add a "\n" to your print statement, so that it is clear what you are doing.	[reply] [d/l]


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