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Jim Gibson wrote: > In article < .com>, > it_says_BALLS_on_your forehead <> wrote: > > > Jim Gibson wrote: > > > In article > > > < s.uwaterloo.ca>, > > > William <> wrote: > > > > > > > On Fri, 6 Jan 2006, wrote: > > > > > > > > > William <> wrote: > > > > > > > > > >> system "grep ''$ticker' $originalList' >> $requiredList"; > > > > > ... > > > > > > > >> > > > > >> I am trying to grep for "USD AA" and "USD SUNW". What is the proper > > > > >> way > > > > >> to "grep"? > > > > > > > > > > You could do the grep from within Perl. Then at least you would have a > > > > > real perl question, rather than a shell and/or gnu utility question. > > > > > > > > I am relatively new to Perl. > > > > how to "grep from within Perl" without using system? > > > > > > Use regular expressions and the print command: > > > > > > #!/usr/local/bin/perl > > > use strict; > > > use warnings; > > > my @search = ( > > > '|USD AA|1|0|', > > > '|USD SUNW|0|1|' > > > ); > > > my @data_lines = <DATA>; > > > foreach my $pattern ( @search ) { > > > my (undef, $ticker) = ( split(/\|/, $pattern), 2 ); > > > print "\nLooking for $ticker:\n"; > > > foreach ( @data_lines ) { > > > print if /\Q$ticker\E/; > > > } > > > } > > > __DATA__ > > > |USD AA|USD NYSE|Securities|1D|0|ATM|18.222100000000001|... > > > |USD AA|USD NYSE|Securities|3D|0|ATM|19.222100000000001|... > > > |USD AA|USD NYSE|Securities|1W|0|ATM|20.8015|20.8015| > > > |USD AA|USD NYSE|Securities|2W|0|ATM|21.4873|21.4873| > > > |USD AA|USD NYSE|Securities|3W|0|ATM|22.2561|22.2561| > > > etc > > > > > > > if you have the array, using grep is cleaner. since it appears that you > > don't need the array, you should just do a regex match in a while loop: > > > > my $pattern = 'wanted'; > > > > while ( <DATA> ) { > > # print or push to array if /$pattern/; > > } > > > > The OP's program was using grep to test a number of patterns against a > single file. The patterns were extracted from the lines in a second > file. Each pattern (e.g. 'USD AA') was used in a system call to the > grep utility. > > The above program does the same thing, except it assigns the pattern > lines to the @search array rather than reading them from a file. This > was done for simplicity. The file containing the data lines is read > from the <DATA> special file handle, again for simplicity. > > Your suggested modification will only test the file against one > pattern. Nor does it use grep, neither the built-in Perl grep nor the > external grep utility. > > So, I don't exactly see what you are suggesting. > > But, thanks for suggesting it anyway!  yeah, it was strange, i posted a response *twice* with a simple program showing the OP how to use grep, but it never showed up. anyway, my suggestion wasn't intended to be directly applicable to the problem at hand, but more of a generic guide which i thought would be more helpful to more people. and the post that i made (the one that didn't show up) answered the OP's question. i'll rewrite it here: the question was: how to "grep from within Perl" without using system? and my code was: #!/usr/bin/perl use strict; use warnings; my @old = qw( hello there keepme ); my @new = grep /keepme/ @old; print "$_\n" for @new; |
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Also sprach Tad McClellan:
> William <> wrote: > > >> Subject: system calls (mv + grep) within Perl script > > > There is no "mv" anywhere in your article. > > It there had been, then I would have pointed you to: > > perldoc rename > > but you didn't, so I won't. And if you had had the intention to point him to rename(), you would have written perldoc -f rename instead, right?  Tassilo -- use bigint; $n=71423350343770280161397026330337371139054411854 220053437565440; $m=-8,;;$_=$n&(0xff)<<$m,,$_>>=$m,,print+chr,,while(($ m+=  <=200); |
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