正则表达式检查小数点是否在两个数字之间，而不管小数点后的位数

Question

Can you help me with writing a Regular Expression ( I will use this in Pattern.compile in Java)?

My requirement is

Given a decimal, should check if the given decimal is between two numbers,

Example: Given Number 1 : 0, Number 2: 50
a) 0 - true
b) 51 - false
c) 50 - true
d) 10.25 - true
e) 10.2345 - true

I should verify irrespective of number of digits after decimal point.

Answer 1

It will be tricky to implement the generic solution, so I'll leave here the solution for your example and let you think of a generic solution for it.

Here's your regex: (([0-4]{1}[0-9]{1})|((50){1}))(\\.[0-9]+)*

To turn it generic you just need to change the first part implementation to the numbers you want to use, you can do it using a loop to concat those groups (this is the first part: ([0-4]{1}[0-9]{1})|((50){1}) ).

Answer 2

So I'm not 100% sure I am understanding the question properly, so I can't be 100% sure it will work for all cases, but here is what I have.

([0-9]{2}\.[0-9]{2})|([0-9]*0\b)

a) 0 - true

b) 51 - false

c) 50 - true

d) 10.25 - true

e) 10.2345 - true

If "." is between 2 Numbers or ends with 0.

Here is the example: https://regex101.com/r/295QWt/1

So my other answer is if a number is between 2 different numbers. Actually in this case I don't think regex is that useful. Depending on the language using regex might even be slower.

if(value > min && value < max){return true;}

Answer 3

Use this regex:

^(?:[0-4]?\d(?:\.\d+)?|50(?:\.0+)?)$

Demo & explanation