Re: which loop is better

There's no real difference in speed. The difference is in structure - for allows you to initialize, increment, and test, while foreach just increments through a list of items. The following are equivalent:

foreach (@arr[0..2]) { $_++; }
for (my $i = 0; $i <= 2; $i++) { @arr[$i]++; }
[download]

The latter offers more control, but isn't necessary for most looping purposes.

Comment on Re: which loop is better Download Code

Replies are listed 'Best First'.
Re^2: which loop is better by Joost (Canon) on Oct 04, 2004 at 10:54 UTC
for and foreach are synonyms. there really is no difference between them: `for (@arr[0..2]) { $_++; } foreach (my $i = 0; $i <= 2; $i++) { @arr[$i]++; }` [download] will work just as well "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re^3: which loop is better by dave_the_m (Monsignor) on Oct 04, 2004 at 11:09 UTC
Err, I don't think what you say is very clear. For and foreach are synonyms, but either of them can be used to delcare two completely different loop contructs, ie the following two lines are identical to each other `for (expr; expr; expr) block foreach (expr; expr; expr) block` [download] while the following two are identical to each other, but not to the first two lines above `for (list) block foreach (list) block` [download] Dave.	[reply] [d/l] [select]
Re^4: which loop is better by Joost (Canon) on Oct 04, 2004 at 11:15 UTC
You're right that I wasn't very clear :-) I meant that the lines in my code where synonyms of the code in the post I was replying to. I meant to say that typing `for` or `foreach` has no impact on the kind of loops you can create with them. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l] [select]