how to split a string and take certain position?

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

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Re: how to split a string and take certain position? by mr_mischief (Monsignor) on Sep 24, 2007 at 04:13 UTC
Your syntax on the first is nearly right. `my $sentence = "5:83:24"; print ( ( split /:/, $sentence )[1] ); # prints 83` [download] Your second one can be done as: `print ( ( split /:/, $sentence )[-1] );` [download] These both use what are known as slices. There's info on slices in perlintro, although I think that just deals with slices of named arrays. List slices specifically are in perldata. Lots of PM nodes have examples of slices as well. Slices can be a little tricky at first, and getting print to see your slice as a single item to print is another issue. Printing the evaluation of the slice accounts for the need to use the outer set of parentheses here.	[reply] [d/l] [select]
Re: how to split a string and take certain position? by mreece (Friar) on Sep 24, 2007 at 04:26 UTC
sure, if you group your parens appropriately -- `(split)[$i]`: `print( (split(/:/, $sentence))[1] ); # negative indexes work too` or the less cluttered: `print +(split /:/, $sentence)[1];` for the latter question, consider: `($match) = $sentence =~ /([^:]+)$/`	[reply] [d/l] [select]
Re: how to split a string and take certain position? by adrive (Scribe) on Sep 24, 2007 at 06:05 UTC
"for the latter question, consider: " `($match) = $sentence =~ /([^:]+)$/` [download] " I can never really understand how string matching works :P why do we need a $ at the end to work? i mean, isn't + already = "One or more of the last character"	[reply] [d/l]
Re^2: how to split a string and take certain position? by ikegami (Patriarch) on Sep 24, 2007 at 06:13 UTC
Your confusing two definitions of "last": "previous" and "ending". `+` means "one or more of the previous atom". `$` (without the `m` option) means "end of string, or a line feed followed by the end of string".	[reply] [d/l] [select]
Re: how to split a string and take certain position? by adrive (Scribe) on Sep 24, 2007 at 04:28 UTC
whoah , i didn't know it worked. print doesn't seem to work if i don't use my split functions enclosed in a bracket. But thanks :)	[reply]
Re^2: how to split a string and take certain position? by erroneousBollock (Curate) on Sep 24, 2007 at 04:34 UTC
There's a general rule: If it looks like a sub-call, it's a sub-call. :-) `print (@somelist)[1]` is treated as `print(@somelist) [1]` which is also a syntax error. -David	[reply] [d/l] [select]
Re^3: how to split a string and take certain position? by ikegami (Patriarch) on Sep 24, 2007 at 04:52 UTC
Two common solutions is two put parens around the function's arguments `print( (@somelist)[1] );` [download] Or put something between the function name and the opening parens, such as the no-op operator `print +(@somelist)[1];` [download]	[reply] [d/l] [select]


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