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Re: Substring comparison
by Corion (Patriarch) on May 01, 2012 at 13:47 UTC
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For plain substring searching, maybe index is enough for you?
As you don't show any code, it's hard to tell, but your original approach of $list1[0] =~ /$list2[0]/ should work as intended. You don't show any code, so it's hard to tell where you went wrong.
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Re: Substring comparison
by JavaFan (Canon) on May 01, 2012 at 13:47 UTC
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Use the index function. It does exactly this. See the manual page. | [reply]
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Re: Substring comparison
by dorko (Prior) on May 01, 2012 at 13:55 UTC
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Please go take a look at List::Compare. I think it will do everything you need and more.
Cheers,
Brent
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Re: Substring comparison
by schtinkfist893 (Novice) on May 01, 2012 at 16:48 UTC
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FOUND IT!
Rookie(which I am) mistake, needed to chomp() in the arrays since the extra whitespace was really messing with the string comparisons
Thanks to everyone's help and ideas!
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Re: Substring comparison
by schtinkfist893 (Novice) on May 01, 2012 at 15:29 UTC
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For some better context here are the Arrays:
Array1
XXX
FFF
ZZZ
AAA
BBB
QQQ
LLL
JKK
III
CCC
DDD
DCD
Array2
XXX BBB AAA CCC DDD EEE
FFF NNN JKK III LLL QQQ
The output
FFF
is not found in FFF NNN JKK III LLL QQQ
ZZZ
is not found in FFF NNN JKK III LLL QQQ
AAA
is not found in FFF NNN JKK III LLL QQQ
BBB
is not found in FFF NNN JKK III LLL QQQ
LLL
is not found in FFF NNN JKK III LLL QQQ
JKK
is not found in FFF NNN JKK III LLL QQQ
III
is not found in FFF NNN JKK III LLL QQQ
CCC
is not found in FFF NNN JKK III LLL QQQ
DDD
is not found in FFF NNN JKK III LLL QQQ
DCD
is not found in FFF NNN JKK III LLL QQQ
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Re: Substring comparison
by schtinkfist893 (Novice) on May 01, 2012 at 15:12 UTC
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I am working with index() and how I am using it with Arrays is not working
foreach(@Array1)
{
$string1 = $_;
foreach(@Array2)
{
my string2 = $_;
my $result = index($string2, $string1);
if($result <= 0)
{
print $string1, " is not found in ", $string2,
+"\n";
}
}
}
My @Array1[0] and $string1 is 'FFF'
My @Array2[0] and $string2 is 'FFF NNN JKK III LLL QQQ'
However my return on the above is
FFF
is not found in FFF NNN JKK III LLL QQQ
Cleary 'FFF' is part of string 'FFF NNN JKK III LLL QQQ' and should return a result >= 0
This code works however when I am not using Arrays
my $string = "FFF NNN JKK III LLL QQQ";
my $substr = "LLL";
my $result = index($string, $substr);
if($result > 0)
{
print "Result: $result\n";
}
else
{
print "not found";
Result: 16
Is there some way I am going about my Array handling incorrect | [reply]
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Re: Substring comparison
by schtinkfist893 (Novice) on May 01, 2012 at 15:42 UTC
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A closer look with some debug out shows that my string QQQ hit and retuned am index value
BBB
and result: -1
BBB
is not found in FFF NNN JKK III LLL QQQ
QQQ
and result: 20
LLL
and result: -1
LLL
is not found in FFF NNN JKK III LLL QQQ
JKK
and result: -1
JKK
is not found in FFF NNN JKK III LLL QQQ
We expect BBB to not return a result, however JKK and LLL should return. | [reply]
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As trammell pointed out index() returns 0 if the sought for string is the beginning. Try this:
@Array1 = qw{XXX FFF ZZZ AAA BBB QQQ LLL JKK III CCC DDD DCD};
@Array2 = ("XXX BBB AAA CCC DDD EEE", "FFF NNN JKK III LLL QQQ");
foreach(@Array1)
{
$string1 = $_;
foreach(@Array2)
{
my $string2 = $_;
my $result = index($string2, $string1);
print $string1, ($result >= 0 ? " IS " : " IS NOT",
+ " found in "), $string2, "\n";
}
}
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Excellent! flaviodesousa solution works for explicitly defined arrays
my @Array1 = qw{XXX FFF ZZZ AAA BBB QQQ LLL JKK III CCC DDD DCD};
my @Array2 = ("XXX BBB AAA CCC DDD EEE", "FFF NNN JKK III LLL QQQ");
XXX IS found in XXX BBB AAA CCC DDD EEE
XXX IS NOT found in FFF NNN JKK III LLL QQQ
FFF IS NOT found in XXX BBB AAA CCC DDD EEE
FFF IS found in FFF NNN JKK III LLL QQQ
However my arrays are being read in from a text file
my $file1 = '/tmp/file1.txt';
my @Array1;
open FILE, $file1 or die $!;
while(<FILE>)
{
@Array1 = <FILE>;
}
my $file2 = '/tmp/file2.txt';
my @Array2;
open FILE, $file2 or die$!;
while(<FILE>)
{
@Array2 = <FILE>;
}
print @Array1;
Print @Array2;
/tmp/file1.txt is as stated above
XXX
FFF
ZZZ
AAA
BBB
QQQ
LLL
JKK
III
CCC
DDD
DCD
/tmp/file2.txt is
XXX BBB AAA CCC DDD EEE
FFF NNN JKK III LLL QQQ
This outputs
FFF
ZZZ
AAA
BBB
QQQ
LLL
JKK
III
CCC
DDD
DCD
FFF NNN JKK III LLL QQQ
So it looks the method I am reading in the Arrays is not as thorough as I expect it to be. | [reply]
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while(<FILE>)
{
@Array1 = <FILE>;
}
That is not going to do quite what you'd hoped. The first time into the loop it will read the first line of the file into the $_ variable, which you never use so that line will be lost. Then, inside the loop you read the file handle in list context as you have an array on the LHS. That will have the effect of reading the remaining lines of the file, one line per element, into the array; the the loop will exit on the next iteration as EOF has been reached. Your array will contain all lines but the first. As you've discovered in your subsequent post you will have to chomp to get rid of line terminators. The correct way to populate your array in a loop would be to use push.
my @arr;
while ( <$fh> )
{
chomp;
push @arr, $_;
}
However, there is an easier way as chomp will also operate on arrays
my @arr = <$fh>;
chomp @arr;
or even
chomp( my @arr = <$fh> );
I hope this is helpful.
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