>>>>> "Pedro" == Pedro A Reche Gallardo <[EMAIL PROTECTED]> writes:
Pedro> Hi all, I have a file that it looks as it follows
Pedro> 1 0.057 M M - M
Pedro> 2 0.819 R R - R
Pedro> 3 0.731 V V - V
Pedro> 4 1.708 K R - c
Pedro> 5 1.070 G G - t
Pedro> 6 1.611 I M - h
Pedro> 7 2.055 + Q - p
Pedro> 8 1.748 + R - +
Pedro> 9 0.864 N N - N
Pedro> 10 2.146 a W - h
Pedro> 11 1.782 Q Q - .
Pedro> 12 2.707 + H - p
Pedro> 13 0.893 . - - .
Pedro> 14 1.252 L L - h
Pedro> 15 0.659 W G - W
Pedro> 16 2.150 + K - p
Pedro> 17 1.137 W W - W
Pedro> 18 0.976 G G - G
Pedro> 19 2.022 . - - .
Pedro> 20 0.147 . - - .
Pedro> 21 0.124 . - - .
Pedro> 22 0.023 . - - .
Pedro> I usually use the following awk comand awk '{if (!($2<0.5&&$3~/\./))
Pedro> print $0}' filename to get rid of the rows where the third column
Pedro> contains the "." caracter, and second column contain a number that is
Pedro> lower than 0.5. In perl the above command -translated using a2p tool-
Pedro> translate into this:
Pedro> #!/usr/sbin/perl
Pedro> eval 'exec /usr/sbin/perl -S $0 ${1+"$@"}'
Pedro> if $running_under_some_shell;
Pedro> # this emulates #! processing on NIH machines.
Pedro> # (remove #! line above if indigestible)
Pedro> eval '$'.$1.'$2;' while $ARGV[0] =~ /^([A-Za-z_0-9]+=)(.*)/ && shift;
Pedro> # process any FOO=bar switches
Pedro> $[ = 1; # set array base to 1
Pedro> $, = ' '; # set output field separator
Pedro> $\ = "\n"; # set output record separator
Pedro> while (<>) {
Pedro> chop; # strip record separator
Pedro> @Fld = split(' ', $_, 9999);
Pedro> if (!($Fld[2] < 0.8 && $Fld[3] =~ /\./)) {
Pedro> print $_;
Pedro> }
Pedro> }
Pedro> I will be very happy if anyone could help me to understand the script. I
Pedro> am particularly lost with the eval function.
The eval is merely used to process FOO=bar switches on the awk
command line. While the above is a nice literal translation of that
awk program, a more Perl-ish translation would be:
while (<>) {
@f = split ' ', $_;
next unless $f[2] < 0.8 and $f[3] =~ /\./;
print;
}
Does that help?
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<[EMAIL PROTECTED]> <URL:http://www.stonehenge.com/merlyn/>
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