Re^3: Perl regex

$ perl -nE '/([^\(]+)\((.*)\)/ and $1 ne $2 and ++$seen{$2} < 2 and sa
+y "$1 : $2"' raw_data.txt
Metan1_4283 : Metac1_3189
MagorCD156_00067621 : MagorUS71_00075311
Phaca1_206503 : Phchr2_2932727
Thite2_36710 : Thiar1_121068
Spoth2_47778 : Thiar1_767720
Micmi1_311120 : Micmi1_478558
Micmi1_478558 : Micmi1_311120
[download]

(Don't use it until you can explain it! Questions welcome.)

The way forward always starts with a minimal test.

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Re^4: Perl regex by Nicpetbio23! (Acolyte) on Jul 12, 2017 at 15:42 UTC
I think I understand most of it. Except -nE and ++ $seen{$2}. `perl : load perl -nE : $1 stands for : ([^$]+) for example Metan1_4283 in Metan1_4283(Metac1 +_3189) $2 stands for : \n((.*)$ for example (Metac1_3189) in Metan1_4283(Met +ac1_3189) $1 ne $2 : Means if first pattern does not match second pattern. ++ $seen{$2} : < 2 : less than 2. say "$1 : $2"' : prints out into two columns. raw_data.txt : path to file goes here.` [download]	[reply] [d/l]
Re^5: Perl regex by 1nickt (Canon) on Jul 12, 2017 at 16:19 UTC
Hi, so one of the greatest things about Perl is its documentation. You can find answers yourself! I Googled for 'perl ++ operand' and got perlop - Perl operators and precedence > Auto increment and Auto decrement. (Here we increment the value stored in `%seen` for each key before making sure that we haven't already seen this key by checking that the value after incrementing is less than 2. Also makes use of Perl's autovivification.) For `-n` and `-E` and all other command line switches for the `perl` executable, see perlrun - how to execute the Perl interpreter. Note that the doc I first pointed you to, perlintro, contains links to all these docs in the overview it gives of each topic. Have you yet allocated a couple of hours of your time to read that document? Seems fair, when you are getting other Monks to give of their time to you. The way forward always starts with a minimal test.	[reply] [d/l] [select]