Re: hash keys

Paul Lalli wrote:
> On Jun 12, 12:15 am, [email protected] (Beast) wrote:
> 
>> Why this following code has not working as expected?
>>
>>     print "Number of element(s) : " . sprintf("%10d", keys(%hash) ) . "\n";
> 
> The keys() function does two different things, depending on context.
> 
> In scalar context, it returns the number of key/value pairs in the
> hash.
> 
> In list context, it returns a list of the keys.
> 
> You probably knew that, but didn't realize that you're using it in a
> list context here.   The arguments to a function are a list,

$ perl -le'print prototype "CORE::sprintf"'
$@

The *second* argument to this *particular* function is a list.


> and so
> Perl is expecting a list of values to be passed to sprintf().

A scalar and a list.  The first argument is interpreted in scalar context:

$ perl -le'@x = "a" .. "z"; print sprintf @x'
26
$ perl -le'print sprintf "a" .. "z"'
1E0




John
-- 
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order.                            -- Larry Wall