Perl字符串比较,不要用==,要用eq
即使是整形,也尽量用eq,少用==
Binary “==” returns true if the left argument is numerically equal to the right argument.
Binary “eq” returns true if the left argument is stringwise equal to the right argument.
Binary "==" returns true if the left argument is numerically equal to the right argument.
Binary "eq" returns true if the left argument is stringwise equal to the right argument.