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Re: Matching string, then getting next line

by inman (Curate)
on Mar 08, 2006 at 10:39 UTC ( #535133=note: print w/ replies, xml ) Need Help??


in reply to Matching string, then getting next line

Hi minixman

It would be worth trying a slightly different approach to the problem. You have mentioned that your content is coming from a file, it would be easier to work with the file itself line by line, look for the match and then do something with the next line. e.g.

while (<MYFILE>){ chomp; #remove line feed if (/do the match here/) { my $nextLine = <MYFILE>; # do stuff with the next line here. } }

This reads the content of the file handle, line by line placing each line into the default $_ variable. You can test to see if you have a match and then take another line from the file.

If you have all of your content in a list then you can substitute the reading of a line from the file with a shift of a line form the list.


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Re^2: Matching string, then getting next line
by minixman (Beadle) on Mar 08, 2006 at 11:09 UTC
    Hi THe problem with that is, that when perl reads my file which was created on windows, it treats the whole file as one line, that is why i had to use FILE::Slurp to split out the lines. So what i need to do is say okay if you match my line, place the value into a variable and then get the next line whatever it is and place that into a variable.
      I guess that you are trying this with a file that has been generated on Windows and then transferred to a UNIX box. You end up with extra ^M chars when you look at the file using vi. Try trimming the surplus whitespace using a regex
      #!/usr/bin/perl -w use strict; while (<MYFILE>){ s/\s+$//; if (/NEXT LINE MARKER/) { my $nextLine = <MYFILE>; $nextLine =~ s/\s+$//; print "$nextLine\n"; # do stuff with the next line here. } }
        That does work, but it splits out the lines that i am looking for so when i run it i end up with.
        #!/usr/bin/perl open(MYFILE, "log.log"); while (<MYFILE>){ s/\s+$//; if (/Message\sdump:/) { my $nextLine = <MYFILE>; $nextLine =~ s/\s+$//; print "Found=$nextLine\n"; # do stuff with the next line here. } }

        Found=23 06/02/23 11:19:34:750 Received FIX message Found=8=FIX.4.29=024935=D34=743=N49=COMPLEX_EXLINK50=DBL9991456=EXLINK +_COMPLEX57=COMPLEXGATE97=N52=20060223-11:18:4660=20060223-11:18:46207 +=XEUR55=XEURFDAX0F2006H200=20060340=259=044=58681=L60954=111=Order58: +1:1140693526109=DBL9991421=238=1167=FUT10=096
        When the format is
        Message dump: 8=TEST.4.29=038435=849=TEST56=TEST50=COMPLEXGATE57=DBL9991134=852=2006 +0223-11:19:351=L6096=0.000011=Order58:1:114069352614=0.000017=11193 54210120=031=0.0000000032=0.000037=132710015138=1.000039=854=155=XEURF +DAX0F2006H58=EUREX Error PRICE60=20060223-11:19:34150=8151=1.0000109= +D BL9991463=0167=TEST=200603207=TEST=244=5868.0000000010=101 25 06/02/23 11:20:00:765 Received TEST message Message dump: 8=TEST.4.29=025135=D34=843=N49=TEST50=TEST=TEST57=COMPLEXGATE97=N52=20 +060223-11:19:1060=20060223-11:19:10207=XEUR55=XEURFDAX0F2006H 200=20060340=259=044=5867.51=L60954=111=Order63:1:1140693551109=DBL999 +1421=238=1167=FUT10=166 26 06/02/23 11:20:01:500 Sent TEST Message Message dump:
      > THe problem with that is, that when perl reads my file
      > which was created on windows, it treats the whole file as one line

      that's odd. most MSDOS/Windows files use CR/LF as the end-of-line marker, but it sounds like your file uses just CR...are you sure it's a DOS file and not a Mac file?

      to read MSDOS/Windows text files, you need to set the input record separator to CR/LF rather than newline (actually, this isn't strictly necessary. if you don't do it, you just end up with a CR at the end of each line. chomp will get rid of it)

      i.e.

      $/="\r\n";

      to read Mac text files, set it to just CR:

      $/="\r";

      see the man page for 'perlvar' for more info.

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