For key-value pair type of lists, hashes are the way to go. I had shown the
other way using a list, which does not need the 'key-value' caveat.
However for your case, Mini, you need to tread the hash path as shown by
Sudarshan.
Here is a code snippet you can try.
#!/usr/bin/perl
my($hash) = {a=>1, b=>2, c=>3, d=>4};
my($key) = 'b';
my($index) = indexOf($hash,$key);
print ("Index of $key in the hash is = $index");
sub indexOf{
my($myHash) = shift;
my($val) = shift;
if(exists $myHash->{$val}){
return $myHash->{$val} ;
}
else{
return("undef"); #WE should not get here if a match is found
}
}
- Rex
-----Original Message-----
From: Sudarsan Raghavan [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, October 03, 2001 8:59 AM
To: [EMAIL PROTECTED]
Cc: Rex Arul; [EMAIL PROTECTED]
Subject: Re: index of an array element
[EMAIL PROTECTED] wrote:
> Rex, in you r previous mail, we explicity need to give
> $str = 'd=4' ; .................It is simple to give it here as I know
the
> key=value pair for d i.e.. d=4. But I want to use function with very large
If it is a list of key=value pairs a hash is the ideal way to go about
it.
>
> lists, and I have to search my list for the key only i.e.. "d".
As I had already mentioned the search for key "d" is simply
$<hashname>{d}
>
>
> thus, what I need is :
> $c = some_func(@list, "d"); .............where some_func should return
> me 3......... Can anybody help me.
Could you pls explain as to why you need only the index? If it is to
check for
its existence
a defined ($<hashname>{d}) will do the job for you. (perldoc -f defined)
>
>
> Please suggest me.
>
> Regards,
> Mini.
>
> "Rex Arul" <[EMAIL PROTECTED]> on 10/03/2001 06:02:30 PM
>
> To: "Sudarsan Raghavan" <[EMAIL PROTECTED]>, Mini
Dwivedi/HSS@HSS
> cc: [EMAIL PROTECTED]
>
> Subject: Re: index of an array element
>
> But that would work only for key=value type of situations.
>
> If @list = (2,'a',100,'cat')
>
> then you cannot rely on Hashes because order cannot be preserved. At such
> instances, you might need to code a custom function as shown in my
previous
> mail.
>
> Right?
>
> -- Rex
>
> ----- Original Message -----
> From: "Sudarsan Raghavan" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Cc: <[EMAIL PROTECTED]>
> Sent: Wednesday, October 03, 2001 8:18 AM
> Subject: Re: index of an array element
>
> > [EMAIL PROTECTED] wrote:
> >
> > > Hi ,
> > >
> > > Say I have an array in perl,
> > >
> > > @list = ("a=3", "b=5", "c=8", "d=9", "e=2", "f=0");
> >
> > looking at your list a hash seems like a better option, the hash will
> be like
> >
> > %hashlist = (
> > a => 3,
> > b => 5,
> > c => 8,
> > d => 9,
> > e => 2,
> > f => 0);
> > the reason being, you are associating the numeric values (3, 5, 8
> etc.) to the
> > characters (a, b, c etc.)
> > a hash (associative array) would be more useful here. Is my
assumption
> correct?
> >
> > To access the element 'd' you will say $hashlist{d}
> > You can get more information on hashes from perldoc perldata
> >
> > >
> > >
> > > Now I want to find the index of the element "d=9" ( Index of d=9 is 3
> here , as
> > > we all know ).
> > >
> > > How do we do that ??
> > >
> > > In perl what I can find that there exist a function "index", which
> returns
> > > position of the substring in string..........like,
> > >
> > > $c = index(@list, "d" );
> >
> > >
> > >
> > > This function will return me the value 13 or 12 perhaps....as the
> substring
> > > "d=9" begins from 13th position in the @list.
> > >
> > > My requirment is :
> > >
> > > $c = some_func(@list, "d"); .............where some_func should return
> me
> > > 3......... Can anybody help me.
> > >
> > > TIA,
> > > -Mini.
> > >
> > > --
> > > To unsubscribe, e-mail: [EMAIL PROTECTED]
> > > For additional commands, e-mail: [EMAIL PROTECTED]
> >
> >
> > --
> > To unsubscribe, e-mail: [EMAIL PROTECTED]
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> >
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