arrays - perl，在for循环中从数组中删除元素

Question

下面的代码总是在 perl 中工作吗？

for loop iterating over @array {
  # do something
  if ($condition) {
     remove current element from @array
  }
}

因为我知道在 Java 中这会导致一些异常，上面的代码现在对我有用，但我想确保它适用于 perl 中的所有情况。谢谢

Answer 1

嗯，这是在doc中说的:

If any part of LIST is an array, foreach will get very confused if you add or remove elements within the loop body, for example with splice. So don't do that.

用 each 好一点:

If you add or delete a hash's elements while iterating over it, entries may be skipped or duplicated--so don't do that. Exception: In the current implementation, it is always safe to delete the item most recently returned by each(), so the following code works properly:

 while (($key, $value) = each %hash) {
    print $key, "\n";
    delete $hash{$key}; # This is safe
  }

但我想这里最好的选择就是使用 grep :

@some_array = grep {
  # do something with $_
  some_condition($_);
} @some_array;