not null cheking of an argument in perl


 
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# 1  
Old 06-05-2007
not null cheking of an argument in perl

Hi,

I have to check whether an argument say $ARGV[1] is not null in an if operator. Please let me know the operator. It would be great if you write a psuedo code.

Thanks in advance
Ammu
# 2  
Old 06-05-2007
A couple of ways to do this.
Code:
VAR=
if [ -z "${VAR}" ] ; then
  echo "VAR contains nothing"
fi

or

Code:
VAR=
if [ x"${VAR}" = x ] ; then
  echo "VAR contains nothing"
fi


edit: My bad. I did not notice that you asked for it in perl

Last edited by vino; 06-05-2007 at 11:03 AM..
# 3  
Old 06-05-2007
Hi Vino,

Thanks for replying. I just want to know whether -z will work in perl script.

if it works then the code should be something like

if ( -z "$ARGV[2]" ) then.....fi


Please correct me if I am wrong

Thanks
Ammu
# 4  
Old 06-05-2007
Code:
if ($ARGV[1] eq "") { print "Empty\n";}

Jean-Pierre.
# 5  
Old 06-05-2007
Quote:
Originally Posted by ammu
Hi Vino,

Thanks for replying. I just want to know whether -z will work in perl script.

if it works then the code should be something like

if ( -z "$ARGV[2]" ) then.....fi


Please correct me if I am wrong

Thanks
Ammu

for not null checking in perl,

how about using
Code:
if ( ! defined $var  ) {
  print "not defined\n";
}
else {
  print "defined\n";
}

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