Re: Internally, how do for() and while() differ?

They are not even close to being equivalent, as evidenced by

my @a = qw( a b c );

for (@a) {
   print("$_\n");   # Prints "a", then "b", then "c".
}

while (@a) {
   print("$_\n");   # Prints an infinite number of blank lines.
}
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Re^2: Internally, how do for() and while() differ? by GotToBTru (Prior) on Oct 27, 2015 at 16:16 UTC
The two examples are equivalent in operation, since they have the <> operator around a file handle. In the case of arrays, which the OP did not specify, you are correct. Unless, again, the <> operator is used. `@a = qw(a b c); for(<@a>) { print "$_\n" }; while(<@a>) { print "$_\n" };` [download] Both produce the same output, the while loop with considerably more efficiency for large datasets. Dum Spiro Spero	[reply] [d/l]
Re^3: Internally, how do for() and while() differ? (readline vs glob) by LanX (Saint) on Oct 28, 2015 at 00:15 UTC
> Unless, again, the <> operator is used. Sorry for nitpicking, but IMHO it's not the same "operator" here. The OP uses a `readline` and you are applying a `glob`.^* That's one of the more confusing magic features of Perl, so I'm open for further discussion on this matter. Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!} ^*) similarly are range and flipflop different, even when written with `..`	[reply] [d/l]
Re^4: Internally, how do for() and while() differ? (readline vs glob) by GotToBTru (Prior) on Oct 28, 2015 at 12:10 UTC
The way 'for' versus 'while' works seems to be a good case for learning how the magic works, at least a little bit. Dum Spiro Spero	[reply]