Why is already explained by others. Here's another alternative: 
for my $x (@{[]} = @arr) {
    ...
}

[download]
this makes a copy of the elements of @arr to loop over, without using a (named) variable.

In reply to Re: Why does a full iteration over array & shift is not emptying the array by JavaFan
in thread Why does a full iteration over array & shift is not emptying the array by Anonymous Monk

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