put only 2 elements in a line

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

Hi Perlmonks.. I want to ask concerning this code below:

print OUT join ";", map {${$_}[1],${$_}[2]} grep { ${$_}[0] eq "EMBL" 
+} $entry->DRs->elements(); 

INPUT :
DR EMBL;ABC;DEF;-.
DR EMBL;GHI;JKL;-
DR PIR;MNO;PQR;-

OUTPUT :
EMBL ABC;DEF;GHI;JKL;
[download]

Basically the $entry->DRs->elements() will return a reference to a list called DR.. in this case we reffered to the list whose first element=EMBL. Is there any way to make my output looks like the input... by modifying the map and grep function above? I tried to separate the map into two parts :

print OUT join ";", map {${$_}[1]}grep { ${$_}[0] eq "EMBL" } $entry->
+DRs->elements(),map {${$_}[2]} grep { ${$_}[0] eq "EMBL" } $entry->DR
+s->elements(),"\n";
[download]

But the print out is still the same... Thanks in advanced...

Comment on put only 2 elements in a line Select or Download Code

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Re: put only 2 elements in a line by chromatic (Archbishop) on Jan 18, 2002 at 12:38 UTC
join will happily slurp up your list. You need a loop of some kind. How's this? `foreach (grep $_->[0] eq 'EMBL') { print OUT "DR EMBL;$_->[0];$_->[1];-.\n"; }` [download] Sorry, no map in there, but I don't think you need it. :) Update: Juerd caught a typo. Fixed!	[reply] [d/l]
Re: put only 2 elements in a line by jryan (Vicar) on Jan 18, 2002 at 13:00 UTC
Chromatic gave an excellent answer, but to answer your original question, this should work: `print OUT map {"DR EMBL: ", join(';',(${$_}[1],${$_}[2])), "\n"} grep +{ ${$_}[0] eq "EMBL" } $entry->DRs->elements();` [download] This will add 3 elements to the list that is the return value of map: The string "DR EMBL: " (using `${$_}[0]` here isn't necessary since the rest of the elements except for EMBL have been filtered out using the grep) A string created by joining the elements `${$_}[1]` and `${$_}[2]` with a semicolon. And finally, a newline I tried to follow the specifications that you wanted, but they weren't exactly clear... If you need something more, just ask.	[reply] [d/l] [select]