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Diffstat (limited to 'pod/perlsyn.pod')
| -rw-r--r-- | pod/perlsyn.pod | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod index 9c3f6617bd..5274d28383 100644 --- a/pod/perlsyn.pod +++ b/pod/perlsyn.pod @@ -270,15 +270,22 @@ implicitly local to the loop and regains its former value upon exiting the loop. If the variable was previously declared with C<my>, it uses that variable instead of the global one, but it's still localized to the loop. (Note that a lexically scoped variable can cause problems -with you have subroutine or format declarations.) +if you have subroutine or format declarations within the loop which +refer to it.) The C<foreach> keyword is actually a synonym for the C<for> keyword, so you can use C<foreach> for readability or C<for> for brevity. If VAR is -omitted, $_ is set to each value. If LIST is an actual array (as opposed -to an expression returning a list value), you can modify each element of -the array by modifying VAR inside the loop. That's because the C<foreach> -loop index variable is an implicit alias for each item in the list that -you're looping over. +omitted, $_ is set to each value. If any element of LIST is an lvalue, +you can modify it by modifying VAR inside the loop. That's because +the C<foreach> loop index variable is an implicit alias for each item +in the list that you're looping over. + +If any part of LIST is an array, C<foreach> will get very confused if +you add or remove elements within the loop body, for example with +C<splice>. So don't do that. + +C<foreach> probably won't do what you expect if VAR is a tied or other +special variable. Don't do that either. Examples: |