Perl -- uc, grep, $_

@array = (1..10）；
map {$_ = $_ * 2}(@array);
结果是@array里的每个元素都乘以2.

@array = qw(apple orange banana plum);
map {$_ = uc($_)} (@array);
#uc 是大写字母

@array = (1..10);
@array2 = grep{$_ > 5} @array;
取array里大于5的元素；

@array = qw(apple orange banana plum);
@array2 = grep{$_ =~ "n"}@array;
显示包含字母"n";