PERL : check + or - sign in a variable

Shell Programming and Scripting
1

I have a variable $max = -3;
It can be $max = +3;

I need to check if this variable is a positive/negative value.
if its positive, should print "positive" if not "negative"

How can this be done?
Thanks in advance

2

Hi,

Just check wheather the variable have value greater than or equal to zero then its positive else negative.

if ( $max >= 0 )
{
   print "Positive\n";
}
else
{
  print "Negative\n";
}

Note: Above works when the variable is integer scalar variable.

if it is string scalar variable, use regex.

if ( $max =~/^\+/ )
{
   print "Positive\n"
}
elsif ( $max =~/^\-/ )
{
  print "Negative\n";
}
else
{
   print "Positive\n";
}
3

Looks like the integer test works with strings as well.

$
$ perl -le '$x = "0"; if ($x >= 0) {print "positive"} else {print "negative"}'
positive
$
$ perl -le '$x = "1"; if ($x >= 0) {print "positive"} else {print "negative"}'
positive
$
$ perl -le '$x = "9"; if ($x >= 0) {print "positive"} else {print "negative"}'
positive
$
$ perl -le '$x = "+9"; if ($x >= 0) {print "positive"} else {print "negative"}'
positive
$
$ perl -le '$x = "+0.99"; if ($x >= 0) {print "positive"} else {print "negative"}'
positive
$
$ perl -le '$x = "-0.99"; if ($x >= 0) {print "positive"} else {print "negative"}'
negative
$
$ perl -le '$x = "-1"; if ($x >= 0) {print "positive"} else {print "negative"}'
negative
$
$

tyler_durden