perl grep with regex

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

Hello

i am trying to match exact match using grep function. I have few values in an array which looks like below

 print "@arr2";

output:
mcs
scr
tsz
unh

print "@arr1";

output:
spec.srn.1235
spec.mcs.1235
[download]

now i am following below operation but it always go to ELSE condition where i would expect for value "spec.mcs.1235" to come in IF condition

 foreach $strfile (@arr1)
       {
       @arr3 = split(/[.\n]/, $strfile);
       if (grep (/^@arr3[1]$/, @arr2)) {
          print "Entered in IF";
       }
       else
       {
          print "Entered in ELSE";
       }
       }
[download]

Could someone let me know what is wrong here? swissknife

Comment on perl grep with regex Select or Download Code

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Re: perl grep with regex by choroba (Cardinal) on Jun 30, 2014 at 12:36 UTC
It works for me: Read more... (625 Bytes) Are you sure your input contains what you think? Try adding the information to the output: `if (grep (/^$arr3[1]$/, @arr2)) { print "Entered in IF Loop: /^$arr3[1]\$/ found in (@arr2)\n"; } else { print "Entered in ELSE Loop: /^$arr3[1]\$/ not found in (@arr2 +)\n"; }` [download] Also note that I used `$arr3[1]` instead of `@arr3[1]`. warnings told me to do so. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^2: perl grep with regex by swissknife (Sexton) on Jun 30, 2014 at 13:33 UTC
Thank you for your response. Does it make any difference when i read arr2 from a file? (in my actual code i get this array by reading a file). i tried as you suggested and got below output. `Entered in else loop: /^mcs$/ found in (scr mcs tsz unh )` [download]	[reply] [d/l]
Re^3: perl grep with regex by choroba (Cardinal) on Jun 30, 2014 at 13:37 UTC
There's probably some whitespace at the end of the lines in the file. Remove it: `s/\s+$// for @arr2;` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^4: perl grep with regex by swissknife (Sexton) on Jun 30, 2014 at 14:20 UTC
Re: perl grep with regex by LanX (Saint) on Jun 30, 2014 at 12:37 UTC
`@arr3[1]` looks very wrong, try `$arr3[1]` Why don't you use `warnings` ? Cheers Rolf (addicted to the Perl Programming Language)	[reply] [d/l] [select]
OT: if loop (was Re: perl grep with regex) by roboticus (Chancellor) on Jun 30, 2014 at 12:55 UTC
swissknife: I have a question: Where did you find the term "if loop"? I've seen it here on perlmonks a few times as of late, and I'm wondering if there's a common source of (mis)information that causes people to think if statements are looping constructs. ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply]
Re: OT: if loop (was Re: perl grep with regex) by swissknife (Sexton) on Jun 30, 2014 at 13:41 UTC
It was completely mistake at my end. Doing lot of things together can make one to make such mistake.	[reply]
Re^2: OT: if loop (was Re: perl grep with regex) by jeffa (Bishop) on Jun 30, 2014 at 14:42 UTC
You really should consider keeping your code properly formatted for maximum readability. Tools like PerlTidy can help you: `foreach $strfile (@arr1) { @arr3 = split(/[.\n]/, $strfile); if (grep (/^@arr3[1]$/, @arr2)) { print "Entered in IF"; } else { print "Entered in ELSE"; } }` [download] jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l] [select]