这个非常简单的正则表达式有什么问题？

Question

I'm trying to test that a regex will match a 2-digit number. I get:

11 =~ /^\d{1,2}$/
# => nil

Yet the regex works flawlessly on Rubular. What am I doing wrong?

Answer 1

The problem is that you are testing the regex against a number and not a string. Regexes are intended for matching strings. Simply:

'11' =~ /^\d{1,2}$/

or

11.to_s =~ /^\d{1,2}$/

Answer 2

You are calling Kernel#=~ , which always returns nil .

Rubular does not interpret your input as Ruby code, it interprets is as string literal. That is why it works there.

Answer 3

您正在对数字而不是字符串应用正则表达式，因此将其转换为字符串并再次尝试。