split's purpose to break down a separated list of items. The first argument of split should normally match the separator, not what you want to extract. 

my $parent = 'xxx xxx xxx';
my $count = my @items = split(/ /, $parent);
print "$count\n";  # 3

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Since you have a count, all you need to check if there are duplicates is check the count. 

if    ($count < 1) { print "None\n";   }
elsif ($count < 2) { print "Unique\n"; } 
else               { print "$count\n"; }

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This is a style/performance question.

It sounds from your description that you can have an input like 

my $parent = 'xxx yyy xxx zzz';

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If so, you should worry about using a *working* solution first. 

my $substring = 'xxx';
my $parent = 'xxx yyy xxx zzz';
my @count = split($substring,$parent);
my $total = $#count + 1;
print "there are $total $substring in $parent\n";   # XXX 3

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This stems from your misuse of split.

In this case, I'd use 

my $substring = 'xxx';
my $parent = 'xxx yyy xxx zzz';
my $count = () = $parent =~ /\Q$substring/;
if    ($count < 1) { print "None\n";   }
elsif ($count < 2) { print "Unique\n"; } 
else               { print "$count\n"; }

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In reply to Re: Counting SubStrings, Style Question by ikegami
in thread Counting SubStrings, Style Question by se@n

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