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Perl code to read from a file

Posted on 2009-07-06
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Last Modified: 2012-05-07
Hello, I have a small stats project to work on.

I am learning perl, but have to learn it in a very short space of time.

Could anyone help me with some code, which would open a text file, draw out 7 comma delineated numbers, ie, 34,56,76,12,1,69,64 and insert them as individual entities into scalar variables ?

thanks

Mick
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Question by:Europa MacDonald
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mrjoltcola earned 2000 total points
ID: 24789471
Here is one way.
#!/usr/bin/perl
 
open(IN, "<test.txt") or die;
 
my $s;
 
while($s = <IN>) {
   if($s =~ /(\d+),(\d+),(\d+),(\d+),(\d+),(\d+),(\d+)/) {
      my ($n1, $n2, $n3, $n4, $n5, $n6, $n7) = ($1, $2, $3, $4, $5, $6, $7);
      print "n1 = $n1,  n7 = $n7\n";
   }
}

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Author Closing Comment

by:Europa MacDonald
ID: 31600371
thankyou
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Author Comment

by:Europa MacDonald
ID: 24789497
it doesn't print to the command line screen, should it ?
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LVL 40

Expert Comment

by:mrjoltcola
ID: 24789514
You are welcome.

Also look at the "split" function, you can split comma separated lines easily with it. I often prefer an explicit regular expression,


my @nums = split /,/, "1,2,3,4,5,6,7"

#!/usr/bin/perl
 
open(IN, "<test.txt") or die;
 
my $s;
 
while($s = <IN>) {
   my @nums = split /,/, $s;
   foreach (@nums) {
      print "$_\n";
   }
}

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Expert Comment

by:mrjoltcola
ID: 24789520
>>it doesn't print to the command line screen, should it ?

Yes, with the test data I used. I made a file test.txt with one line of text:  34,56,76,12,1,69,64

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Author Comment

by:Europa MacDonald
ID: 24789523
I am using windows, should this make a difference ?
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Author Comment

by:Europa MacDonald
ID: 24789532
I apologise, it did that time.
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