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Perl - use search keywords from array and search a file and print 3rd field when matched


 
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# 1  
Old 12-13-2012
Perl - use search keywords from array and search a file and print 3rd field when matched

Hi ,

I have been trying to write a perl script to do this job. But i am not able to achieve the desired result. Below is my code.

Code:
my $current_value=12345;
my @users=("bob","ben","tom","harry");
open DBLIST,"<","/var/tmp/DBinfo";
my @input = <DBLIST>;

foreach (@users)
{
my $req_user_info=grep(/$_/,@input);
my ($user,$blah,$value)=split(/:/,$req_user_info);
my $diff=$current_value-$value;
print "$diff";
}}

Can some please help me understand what i am missing and how to edit this code to get the desired result.
# 2  
Old 12-13-2012
Hi

It would have been better had your provided a sample input file of yours. At hindsight, this is one issue:

Code:
foreach  my $x (@users)
{
my $req_user_info=grep(/$x/,@input);
my ($user,$blah,$value)=split(/:/,$req_user_info);
my $diff=$current_value-$value;
print "$diff";
}

Guru.
# 3  
Old 12-13-2012
@ Guru , i am using perl default variable $_ . Hence i have not used a separate variable in foreach loop.
# 4  
Old 12-13-2012
@chidori : Did you try the above solution? I understand you tried to use $_, but it should not be used when using grep. This is because grep internally uses $_ to process each element of the array.

Guru.
# 5  
Old 12-13-2012
i can see
Code:
my $req_user_info=grep(/$x/,@input);

the output of grep looks like "0" and "1" so the variable $req_user_info is holding numbers. but i would require something like search for the pattern and when match is found store that line in variable
# 6  
Old 12-13-2012
Hi
You should use it like this:

Code:
my ($req_user_info)=grep(/$x/,@input);

This is because grep returns a list, and when used in scalar context, you get the length.

Guru.
This User Gave Thanks to guruprasadpr For This Post:
# 7  
Old 12-13-2012
It worked!!!

Thanks Guru.. It worked Smilie

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