爲什麼map函數在perl中改變輸入數組的值？

Question

爲什麼map函數在perl中改變輸入數組的值？ 爲了說明，

#!/usr/bin/env perl 


use strict; 
use warnings; 
use v5.10; 


my @words = <DATA>; 

# want to have another array that contains the each word in reverse order 
my @reverse_words = map { $_ = scalar reverse $_ } @words; 

say $words[0]; # want to check the content of first element of original array 
say $reverse_words[0]; # new 



__DATA__ 
aarhus 
aaron 
ababa 
aback 

但這打印

$perl findPalindrome.pl 

suhraa 

suhraa 

爲什麼原數組改變？

Answer 1

因爲您通過修改$_來提問。

你想

my @reverse_words = map { scalar reverse $_ } @words;