nested if else

sarvan has asked for the wisdom of the Perl Monks concerning the following question:

Hi there,

I have the following code with nested if else. Two if conditions are nested. In the first if i check on condition. if it satisfies then go into the 2nd if. In the 2nd if i route the prgm to different other programs based on the condition satisfied.

But, now it takes me directly to the else of 1st if without executing the 2nd if and its condition's. I have no idea where i did mistake. Can anyone help me.


#!/usr/bin/perl

use strict;
use warnings;
print "Which Metric jaccard or Bleu:";
my $metric=<>;
print "Which source title or snippet or url:";
my $source=<>;
if($metric eq "jaccard")
{
if($source eq "title")
{
print "in title";
system("/usr/bin/perl filecom.pl")
}
elsif($source eq "snippet")
{
print "in snippet";
system("/usr/bin/perl searchsnipdup.pl")
}
elsif($source eq "url")
{
print "in url";
print"jaccard method not called";
}
else
{
print "jacccard not called";
}
}
elsif($metric eq "bleu")
{
print "bleu called";
}
else
{
print "bleu not called";
}
[download]

Comment on nested if else Download Code

Replies are listed 'Best First'.
Re: nested if else by kcott (Archbishop) on Jul 13, 2011 at 06:07 UTC
Your problem is that you're doing an exact match (with `eq`) against the alphabetic characters but not the terminal newline. For example, if I type in jaccard, then `$metric` will be the string `"jaccard\n"`. You should probably chomp the input prior to processing it, e.g. `my $metric = <>; chomp $metric;` [download] Example of your code as posted: `Which Metric jaccard or Bleu:jaccard Which source title or snippet or url:title bleu not called` [download] Example after chomping `$metric` and `$source`: `Which Metric jaccard or Bleu:jaccard Which source title or snippet or url:title in title` [download] P.S. I also notice you prompt for "Bleu" but test for "bleu": these strings are not equal. -- Ken	[reply] [d/l] [select]
Re: nested if else by lidden (Curate) on Jul 13, 2011 at 06:04 UTC
Your variables will contain newline chars. All your `if`s will fail. Try `chomp $metric;` after you have read something into it.	[reply] [d/l] [select]
Re: nested if else by Marshall (Canon) on Jul 13, 2011 at 13:47 UTC
Appropriate use of white space is one of the most important things that you can do to improve program legibility. use strict; use warnings; print "Which Metric jaccard or Bleu:"; my $metric=<>; chomp $metric; print "Which source title or snippet or url:"; my $source=<>; chomp $source; if($metric eq "jaccard") { if($source eq "title") { print "in title"; system("/usr/bin/perl filecom.pl") } elsif($source eq "snippet") { print "in snippet"; system("/usr/bin/perl searchsnipdup.pl") } elsif($source eq "url") { print "in url"; print"jaccard method not called"; } else { print "jacccard not called"; } } elsif($metric eq "bleu") { print "bleu called"; } else { print "bleu not called"; } [download]	[reply] [d/l]
Re: nested if else by BrowserUk (Patriarch) on Jul 13, 2011 at 05:24 UTC
Have you heard the word "indentation"?	[reply]