Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses
 
PerlMonks  

Re: C-style for loop

by zentara (Archbishop)
on Nov 15, 2008 at 19:18 UTC ( #723830=note: print w/replies, xml ) Need Help??


in reply to C-style for loop

The C-style loop can be useful in cases where you want to skip over some values, but for other reasons(possibly ease of remembering range) want to keep your range 0..100. 
#!/usr/bin/perl

for (my $i = 0; $i <= 100; $i += 5) {
   print($i, "\n");
}

print "\n";

for (0..20){
     print 5 * $_,"\n";
}

[download]
Someone good at setting up efficiency tests, may find one better than the other in terms of what is fastest.
I'm not really a human, but I play one on earth Remember How Lucky You Are

Replies are listed 'Best First'.
Re^2: C-style for loop
by zentara (Archbishop) on Nov 15, 2008 at 19:31 UTC
    Looks like Perl is faster in this case. 
    #!/usr/bin/perl
use warnings;
use strict;
use Benchmark; 

#Outputs:
#Benchmark: timing 1000000 iterations of c-loop, perl-loop...
# c-loop:  5 wallclock secs ( 5.64 usr +  0.02 sys =  5.66 CPU) 
            @ 176678.45/s (n=1000000)
# perl-loop:  3 wallclock secs ( 3.58 usr +  0.01 sys =  3.59 CPU) 
           @ 278551.53/s (n=1000000)


timethese(1000000, {

'c-loop' => sub {

 for (my $i = 0; $i <= 100; $i += 5) {
   #print("$i ");
  }

}, 

'perl-loop' => sub {

  for (0..20){
    # print 5 * $_." ";
  }
 
 },

});

    [download]
    I'm not really a human, but I play one on earth Remember How Lucky You Are
[reply]
[d/l]

In Section Seekers of Perl Wisdom

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://723830]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others rifling through the Monastery: (4)
As of 2021-02-28 01:31 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found
    Notices?