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perl : semi complex if statement question

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# 1  
Old 11-17-2009
perl : semi complex if statement question
Hi there

I am trying to write an if statement in perl that will return "SUCCESS" if either of these conditions are true

a) if $changes is greater than 5 AND the $force flag is set to 1

OR

b) if $changes is greater than 0 AND $changes is less than 6


Code:
#!/usr/bin/perl -w

my $force = "0";
my $changes = "7";


if ((($changes gt "5") && ($force = "1")) || (($changes gt "0") && ($changes lt "6"))) {
        print "success\n";
} else {
        print "failure\n";
}

My script seems to be syntactically correct, however, whatever i set the $changes and $force values to, it always reports "success" .... is there something im doing wrong here ??

any help would be great
# 2  
Old 11-17-2009
try using eq instead of =
# 3  
Old 11-17-2009
thanks

---------- Post updated at 04:56 PM ---------- Previous update was at 07:47 AM ----------

actually, sorry, i replied a bit prematurely . it still doesnt work ... im still getting success when I go over the value "9" on $changes, ill give an example. Although your suggestion does at least make the statement work up to the value 9, but not beyond ...

Code:
#!/usr/bin/perl -w

my $force = "0";
my $changes = "9";

if ((( $changes gt "5" ) && ( $force eq "1" )) || (( $changes gt "0" ) && ( $changes lt "6" ))) {
        print "success\n";
} else {
        print "failure\n";
}

Code:
# test.pl
failure
#

but now when i switch the value of $changes to "10", it for some reason returns true

Code:
#!/usr/bin/perl -w

my $force = "0";
my $changes = "10";

if ((( $changes gt "5" ) && ( $force eq "1" )) || (( $changes gt "0" ) && ( $changes lt "6" ))) {
        print "success\n";
} else {
        print "failure\n";
}

Code:
# test.pl
success
#

Could anybody explain to me whats going on here ?, its driving me crazy Smilie
# 4  
Old 11-17-2009
Hi, you are using string values and string operators instead of numerical operators. Try:
Code:
#!/usr/bin/perl -w

my $force = 0;
my $changes = 10 ;

if ((( $changes > 5 ) && ( $force == 1 )) || (( $changes > 0 ) && ( $changes < 6 ))) {
  print "success\n";
} else {
  print "failure\n";
}

# 5  
Old 11-17-2009
Quote:
Originally Posted by rethink
... your suggestion does at least make the statement work up to the value 9, but not beyond ...
In addition to Scrutinizer's response, you may want to recall that string comparison is ASCII-value comparison.
Which is why these scripts behave the way they do:

Code:
$
$ perl -le '$x="9"; if ($x gt "5") {print "$x gt 5"} else {print "$x le 5"}'
9 gt 5
$
$ perl -le '$x="10"; if ($x gt "5") {print "$x gt 5"} else {print "$x le 5"}'
10 le 5
$
$

tyler_durden
# 6  
Old 11-19-2009
thanks Guys, my logic was that if you had operators like "lt" "gt" "eq" etc, it would be logical to use those ones for numerical comparisons and the "=" etc for strings .... but i guess the perl guys didnt agree

thanks again
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