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Re: Simple prog isnt cooperating
by pryrt (Abbot) on Oct 15, 2018 at 21:50 UTC
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I see three typos/issues:
- $Namelist ~= m/\w+a/ should be $Namelist =~ m/\w+a/ -- tilde after equal sign for pattern match
- print "Matched|$<$&>$|\n" should be print "Matched|$<$&$>|\n" -- sigil before greater-than, not after, for special variable
- You have no parenthetical phrases in your match, so $1 doesn't match anything. If you want to get the name, use parens around the match: m/(\w+a)/
(stevieb beat me to #1 and #3)
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Wait, I don't think you want most of those special variables in your print. ($< being UID, $> being EUID, $| being autoflush... I think you did mean $& as the match). Were you trying to escape the <, >, and/or | ? What were you trying to do with those?
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Sir,
What I'm trying to accomplish is to pull a name from the list and print it out. I have done this various ways, but I'm trying to do this as requested in chapter 8, exercise #3 in the 'Learning Pearl' book by O'Reilly. I have corrected all of the typos that were pointed out,(very humbling that I did not pick up on that). I am still running into problems.
#!/bin/perl
use v5.12;
use warnings;
my $Namelist = 'Wilma Fred Barney Betty Dino';
if ( $Namelist =~ m/(\w+a)/ {
print "Matched|$<$&$>|\n";
say "The name that matched was $1 \n";
} else {
print "No match: \n";
}
syntax error at ./exer_8_3 line 8, near "m/(\w+a)/ {"
syntax error at ./exer_8_3 line 11, near "}"
Thanks again,
Catfish | [reply]
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You (pryrt) are one of the most loyal, honest and trustworthy persons I've ever met regarding code. I'm sorry I beat you to the punch here ;)
You have not only "assisted" me on extremely major projects, but actually wrote, and re-wrote code on behalf of our (yes, our) major berrybrew project, including *massive, major and new* test scenarios and functionality.
If I could give you the Perlmonks XP, I would :P
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Re: Simple prog isnt cooperating
by stevieb (Canon) on Oct 15, 2018 at 21:45 UTC
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In if($Namelist ~= ...), I think you meant:
=~. That's the "equals or contains" regex check. ~= doesn't mean much to perl.
Also, $1 is a special variable based on a regex capture. You're not capturing anything here. A capture in a regex is specified by parens. I've got a meeting to bounce to, so someone else will have to explain that issue.
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Yet Another Boring Meeting (where when I'm not needed, I hack Perl). Here's the capture you need. Note that it was quick and dirty, so I have not inserted any checking at all (which should be promoted; always check the value of a capture):
use v5.12;
use warnings;
my $Namelist = 'Wilma Fred Barney Betty Dino';
if ( $Namelist =~ m/(\w+a)/) {
print "Matched|$<$&>$|\n";
say "The name that matched was $1 \n";
}
else {
print "No match: \n";
}
Output:
spek@scelia ~/scratch $ perl format.pl
Matched|1000Wilma>0
The name that matched was Wilma
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Re: Simple prog isnt cooperating
by stevieb (Canon) on Oct 15, 2018 at 21:38 UTC
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Welcome to the Monastery, catfish1116!
Please put your programming code within <code>code here...</code> code tags, per Writeup Formatting Tips.
For the Monks, here it is formatted and within proper tags:
use v5.12;
use warnings;
my $Namelist = 'Wilma Fred Barney Betty Dino';
if ( $Namelist ~= m/\w+a/) {
print "Matched|$<$&>$|\n";
say "The name that matched was $1 \n";
}
else {
print "No match: \n";
}
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