I am trying to match and extract numbers if:

• They are not a single 2
• They are not a single 4
• They are not a 4-digit number

*Note: Placement of numbers in the string is completely random - the numbers can occur at the beginning, middle, or end and can be any length other than 4.

Here is a table with examples of strings and desired matches.

I found an SO article that begins to address the single 2 and single 4 issue here. The regex I have thus far is '\b(?!2\b|4\b|\d{4})\d \b', but that requires the numbers to be standalone (surrounded by spaces) and also will not extract numbers that have 4 digits, but exceed it (e.g. 1234567). I'd appreciate some help if anyone has some ideas.

CodePudding user response：

You could use negative lookarounds (?<!\d) and (?!\d) as boundaries:

(?<!\d)(?!([24]|\d{4})(?!\d))\d 

See this demo at regex101

Inside the first negative lookahead disallowed numbers get alternated in a group.