如何使哈希键查找不区分大小写？

Question

显然,哈希密钥以区分大小写的方式进行比较.

$ perl -e '%hash = ( FOO => 1 ); printf "%s\n", ( exists $hash{foo} ) ? "Yes" : "No";'
No

$ perl -e '%hash = ( FOO => 1 ); printf "%s\n", ( exists $hash{FOO} ) ? "Yes" : "No";'
Yes

是否有更改当前脚本的设置？

Answer 1

您将不得不使用绑定哈希.例如Hash :: Case :: Preserve.

Answer 2

字符串的散列和更改大小写的相同字符串不相等.因此,除非在创建它之前在每个哈希键上调用"uc"并且在使用它之前,否则无法执行所需操作.

Answer 3

my %hash = (FOO => 1);
my $key = 'fOo'; # or 'foo' for that matter

my %lookup = map {(lc $_, $hash{$_})} keys %hash;
printf "%s\n", ( exists $hash{(lc $key)} ) ? "Yes" : "No";