Question

I am trying to write a Java Script regex to match if a string contains only allowed characters in following manner –

1. String shall have only 0, 1, x or comma (,) in it.
2. Each number (0, 1 or “x”) shall be separated by a comma (,)
3. There shall be at least one comma separated value (i.e. “0,1” or “0,x,1”)
4. The comma shall always be surrounded by numbers or “x” (i.e. “,” or “,0” is invalid )

Is it possible to write a regex for this condition? I am able to do it using java script string split but that does not appear elegant to me. Hope someone could help come up with a regex for above condition.

Answer 1

Although I agree with @SomeKittens that you should show what you tried, you at least provided a fairly detailed spec. Based on my understanding of it, you can use something like this:


var isValid = /^(?:[01x],)+[01x]$/.test(str);


That matches any of these:

• 0,1
• 0,1,1
• 0,x,0,0

And none of these:

• 0
• ,
• 0,
• 0,1,
• ,1
• 0,,1
• 0,X (uppercase X)

If you want to allow matching uppercase Xs in addition to lowercase, add the /i flag to the regex for case insensitive matching.