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Re: Is there an InString-like function?
by simon.proctor (Vicar) on Jul 23, 2001 at 16:11 UTC
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Personally I've not heard of anything like this, however if I needed to do it I'd do it as a sub and pass it an array reference
if(in($var,$array))
{
print "Yes!!!!";
}
else
{
print "No!!!";
}
sub in
{
my $var = shift;
my $ref = shift;
foreach (@{$ref})
{
if($var == $_)
{
return 1;
}
}
return 0;
}
That should work but its my dinner hour and I'm munching as well :) | [reply]
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You've heard of grep, right?
print grep { $_ eq $var } qw( 1 2 3 4 5 ) ? "Found.\n" : "Not found.\n
+";
Note though that grep loops over the entire array everytime, so for large arrays, simon.proctor's function would be better.
[ ar0n ]
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Thanks, this is perfect. I was looking for something better than index and you example works great, especially since I am running the test against many multi-lenth strings, not single characters. Unfortunately, the documentation on the "grep BLOCK LIST" is severly lacking so I appreciate your insight. If I ever need to work with long lists, I will use a pattern matching solution like the one given by wiz which also works well.
Thanks again,
tigervamp
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Re: Is there an InString-like function?
by ariels (Curate) on Jul 23, 2001 at 16:22 UTC
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Look at index. It finds substrings.
Your example was slightly misleading: index $var, "1,2,3,4,5" >= 0 is not a good way to test if $var is one of these values (as you yourself note). This may have confused some respondents.
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Re: Is there an InString-like function?
by Hofmator (Curate) on Jul 23, 2001 at 16:53 UTC
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or in some languages if the first character of the string $var is 1,2,3,4 or 5
Well, in perl we 'only' have the scalar type, but you can use it as a string. Then a regex might be your solution, TIMTOWTDI. For your example you'd write:
print '$var starts with 1, 2, 3, 4 or 5' if ($var =~ /^[12345]/);
print '$var contains 1, 2, 3, 4 and/or 5' if ($var =~ /[12345]/);
print '$var starts with 1, 2, 3, 4 or 5' if ($var =~ /^[12345]/);
and you can do a lot of further nice things with regexes, have a look at our Tutorials.
As a remark, this method only works for simple cases, if you want something like $var in (12, 25, 100..233) then a regex is not ideal. Consider the other solutions presented so far for these cases.
-- Hofmator
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Re: Is there an InString-like function?
by mattr (Curate) on Jul 23, 2001 at 17:19 UTC
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I'm a little confused by what you want. The index
and grep commands, a regular expression, or querying a hash
for the existence of a key are all possible answers.
In the case of a hash, the key is a (hopefully) unique
number calculated from your input so you have to do
alphabetic sorting by hand.
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To help your confusion, any maybe somebody else's...
Take SQL for example:
select name
from phone_book
where last_name in ("Smith","Jones","Schmidtz")
Hope this helps..
_14k4 - perlmonks@poorheart.com (www.poorheart.com) | [reply]
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In this case, there is a very easy way of doing this.
Now all you really have to do it go if ($var =~ /^[12345]/).
Now if you wanted to do a search through strings, i would suggest going, if ($var =~ /^[qw(Smith Jones Schmidtz)]/).
I tested both scripts on Win2k and Active Perl 5.6.1. So basically it works to if ($variable =~ /^##data to search through here##/). this means if $variable finds that any of the search variables are true (if you don't use ^ then it does an and/or search), it does it's required task.
Update:
With help from many people, when doing a string search, drop the [] from a string search, or else your searching through the characters of the string.
----------------------------
Wiz, The VooDoo Doll
Head Master of 12:30 Productions
----------------------------
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Re: Is there an InString-like function?
by CharlesClarkson (Curate) on Jul 24, 2001 at 03:48 UTC
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If you feel you may one day port to a quantum computer, you might have the foresight to use the any function in Quantum::Superpositions
use Quantum::Superpositions;
if ( $var == any(1 .. 5) ) {
HTH,
Charles K. Clarkson
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