perl - perl 中的 for 循环

Question

my @array=(1..10);
for my $i (@array){$i++;}
print "array is now:@array";

这是改变数组的值。为什么？

Answer 1

这就是 Perl 中的 for 语句定义的目的。请参阅 Foreach Loops 的文档在 man perlsyn 中:

If any element of LIST is an lvalue, you can modify it by modifying VAR inside the loop. Conversely, if any element of LIST is NOT an lvalue, any attempt to modify that element will fail. In other words, the foreach loop index variable is an implicit alias for each item in the list that you're looping over.