Matching Operators

rolandomantilla has asked for the wisdom of the Perl Monks concerning the following question:

If a file with three different lines of text for examples:

gcl161 tts30 RM 02
gc116  tts20 RM 02
gc11   tts21 RM 23
[download]

and then if I have matching operators like

if (/tts\s0./) {print;}
if (/[tts30]/] {print;}
or somthing like
if (/^[23]/) {print;}
[download]

Which line or which part will print?

Comment on Matching Operators Select or Download Code

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Re: Stupid question by pemungkah (Priest) on Aug 19, 2011 at 06:43 UTC
Let's assume you've read these lines in one at a time into `$_`, using something like this: `open my $file, "<", "my.file" or die "Can't open my file: $!"; while(<$file>) { # $_ has the current line print if /tts\s0./; print if /[tts30]/; print if /^[23]/; }` [download] The first pattern would not print anything, because it's looking for "tts", one whitespace character immediately after the "tts" (with no intervening characters), then a zero, then any one character other than a newline. The second would print the first and last lines, because it's looking to find one copy of either t, s, 3, or 0, anywhere in the line. The last one would print nothing, because it wants either a 2 or 3 at the beginning (the '^') of the line. You can try things like this in the debugger by starting it up with `perl -demo`, setting `$_` to the line you want to match against, and then entering the `print if` lines, changing `$_` to try the different data lines.	[reply] [d/l]
Re: Stupid question by Anonymous Monk on Aug 19, 2011 at 06:32 UTC
would it work like a regular expression? What it are you talking about? The match operator? Have you read perlintro? I guess I'm confused due to how the question is worded. What question? See How do I post a question effectively? "Stupid question" is textbook ineffective node title, see How do I compose an effective node title?	[reply]
Re: Matching Operators by GotToBTru (Prior) on Aug 19, 2011 at 14:42 UTC
Try it and see. If the results are not what you expect, consult perlre. If you still don't understand, ask. Hint: it helps if your question doesn't look like a problem posed on a skills assessment for a job posting.	[reply]