Re^2: Splitting in while loop

In non-slurp mode, this works via assignment using the diamond operator (<>) - or just the same if you open an file handle, $FH:

# test.pl
while (my $line = <>) {
  chomp $line;
  print qq{$line\n}; # yes I know, pointless use of chomp
}
[download]

> perl test.pl < test.pl
# test.pl
while (my $line = <>) {
  chomp $line;
  print qq{$line\n}; # yes I know, pointless use of chomp
}
[download]

Similarly, you could do something destructive with pop or shift, like,

while (my $item = pop @my_array) {
  # do stuff with $item
}
[download]

Comment on Re^2: Splitting in while loop Select or Download Code

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Re^3: Splitting in while loop by haukex (Archbishop) on Oct 12, 2021 at 16:41 UTC
`while (my $line = <>)` ... Similarly, ... `while (my $item = pop @my_array)` `use warnings; use strict; while (my $line = <DATA>) { chomp $line; print "<$line>\n"; } my @array = ("Foo","0","Bar"); while (my $item = pop @array) { print "[$item]\n"; } __DATA__ Hello 0 World` [download] Outputs: `<Hello> <0> <> <World> [Bar]` [download] I'd call that a pretty serious caveat. As per I/O Operators, the first is equivalent to `while ( defined( my $line = <> ) )`, and readline returns `undef` at EOF, while the second one will stop at any false value, and arrays can contain `undef`s too.	[reply] [d/l] [select]

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Re^3: Splitting in while loop
by haukex (Archbishop) on Oct 12, 2021 at 16:41 UTC

while (my $line = <>) ... Similarly, ... while (my $item = pop @my_array)

use warnings;
use strict;

while (my $line = <DATA>) {
    chomp $line;
    print "<$line>\n";
}

my @array = ("Foo","0","Bar");
while (my $item = pop @array) {
    print "[$item]\n";
}

__DATA__
Hello
0

World
[download]

Outputs:

<Hello>
<0>
<>
<World>
[Bar]
[download]

I'd call that a pretty serious caveat. As per I/O Operators, the first is equivalent to while ( defined( my $line = <> ) ), and readline returns undef at EOF, while the second one will stop at any false value, and arrays can contain undefs too.

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