正则表达式匹配只有2个大写字母的字符串

Question

I want to write a regex which will match a string only if the string consists of two capital letters.

I tried - [AZ]{2}, [AZ]{2, 2} and [AZ][AZ] but these only match the string 'CAS' while I am looking to match only if the string is two capital letters like 'CA'.

Answer 1

You could use anchors:

^[A-Z]{2}$

^ matches the beginning of the string, while $ matches its end.

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Note in your attempts, you used [AZ]{2, 2} which should actually be [AZ]{2,2} (without space) to mean the same thing as the others.

Answer 2

You need to add word boundaries,

\b[A-Z]{2}\b

DEMO

Explanation:

• \\b Matches between a word character and a non-word character.
• [AZ]{2} Matches exactly two capital letters.
• \\b Matches between a word character and a non-word character.

Answer 3

You could try:

\b[A-Z]{2}\b 

\\b matches a word boundary.

Answer 4

Try =

^[A-Z][A-Z]$ 

Just added start and end points for the string.