正则表达式匹配最多 2 位数字和最多 2 位小数的数字

Question

I've been searching for the past few days but the only kinds of regex that I find are like this:

(\d{0,2})\.?\d{1,2}$

This works well with inputs like:

9
99
9.9
9.99
99.9
99.99
.9
.99

Everything's OK with those, but it also happens to accept inputs like

999
9999

I don't want this to happen. What can I do to solve this problem?

Answer 1

You can use this regex with alternation:

^(?:\d{1,2}|\d{0,2}\.\d{1,2})$

RegEx Demo

RegEx Description:

^           # start
(?:         # start non-capturing group
   \d{1,2}  # match 1 or 2 digits
   |        # OR
   \d{0,2}  # match 0 to 2 digits
   \.       # followed by DOT
   \d{1,2}  # match 1 or 2 digits
)           # end non-capturing group
$           # end

Answer 2

使用以下正则表达式

(\d{0,2})\.\.?\d{0,2}$