以 2 个字母开头并以 3 个字母结尾的匹配正则表达式

Question

Example input:

'Please find the ref AB45676785567XYZ. which is used to identify reference number'

Example output:

'AB45676785567XYZ'

I need a RegExp to return the match exactly matching my requirements; ie the substring where the first 2 and last 3 characters are letters.

The first 2 and last 3 letters are unknown.

I've tried this RegExp :

[a-zA-Z]{2}[^\s]*?[a-zA-Z]{3}

But it is not matching as intended.

Answer 1

Your current RegExp matches the following words marked with code blocks:

Please find the ref AB45676785567XYZ . which is used to identify reference number

This is because your RegExp , [a-zA-Z]{2}[^\\s]*?[a-zA-Z]{3} , is asking for:

• [a-zA-Z]{2} Begins with 2 letters (either case)
• [^\\s]*? Contains anything that isn't a whitespace
• [a-zA-Z]{3} Ends with 3 letters (either case)

In your current example, restricting the letters to uppercase only would match only the match you seek:

[A-Z]{2}[^\s]+[A-Z]{3}

Alternatively, requiring numbers between the 2 beginning and 3 ending letters would also produce the match you want:

[a-zA-Z]{2}\d+[a-zA-Z]{3}

Answer 2

Start with 2 letters :

[a-zA-Z]{2}

Digits in the middle :

\d+

Finish with 3 letters :

[a-zA-Z]{3}

Full Regex :

[a-zA-Z]{2}\d+[a-zA-Z]{3}

If the middle text is Alpha-Numeric, you can use this :

[A-Z]{2}[^\s]+[A-Z]{3}

Answer 3

What is really important here, is word boundaries \\b , try: \\b[a-zA-Z]{2}\\w+[a-zA-Z]{3}\\b

Explanation:

\\b - word boundary

[a-zA-Z]{2} - match any letter, 2 times

\\w+ - match one or more word characters

[a-zA-Z]{3} - match any letter, 3 times

\\b - word boundary

Demo

CAUTION your requirements are amibgious, as any word consisting of 5 or more letters would match the pattern