Hi,
you could try using grep on the keys, e.g.:
my %hash = ( a => 'a', b=> 'b', 3 => 'three');
($val) = @hash{grep /^\d/, keys %hash};
print "val = '$val'\n";
;)
Dave
-----Original Message-----
From: Eric Beaudoin [mailto:[EMAIL PROTECTED]]
Sent: 13 August 2001 00:15
To: Birgit Kellner
Cc: [EMAIL PROTECTED]
Subject: Re: finding a key in a hash with regexp
At 18:25 2001.08.12, Birgit Kellner wrote:
>Hm, what's the shortest way to do this: I have a hash where one, and only
one, key begins with a number, I don't know its value and want to assign
this value to a variable.
>
>If I were to do a foreach loop, I'd do this (presuming that %hash is
already defined):
>
>foreach my $key(keys %hash) {
> if ($key =~ /^\d/) {push (@keys, $key); }
>}
>
>But since I know there will only be one key where this condition is true,
looping and creating an array seems like a waste.
>
>
>Birgit Kellner
How about :
foreach my $key (sort keys %hash)
{
if ($key =~ /^\d/) {
push (@keys, $key); # Put the key in the keys list
last; # Exit the loop, do not proccess the rest of %hash.
}
}
Since sorting a list is faster than processing each element of it and since
numbers are sorted before letters, you should find your number very fast.
If you are looking for other type of data, you could make yourself a special
sort.
You could also use the grep command and generate a list with only the keys
that match the regex. As in
my $key = (grep /^d/, (keys %hash))[0]; # Find one key begining with a
number.
push (@keys, $key); # Put the key in the keys list.
Hope it helps.
-----------------------------------------------------------
Éric Beaudoin <mailto:[EMAIL PROTECTED]>
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