Consecutive uppercase letters regex

Question

I'm trying to use Regular expressions to find three consecutive uppercase letters within a string. I've tried using: ``` \b([A-Z]){3}\b ``` as my regex which works to an extent. However this only returns strings by themselves. I also want it to find three consecutive uppercase letters nested within a string. i.e `thisISAtest`.

Accepted Answer

I wonder why you have those word boundaries in your regexp `\b`? Word boundaries ensure that an word character is followed by a non-word character (or vice versa). Those are what prevents `thisISAtest` from being matched. Remove them and you should be good!

```
([A-Z]){3}
```

Another thing is that I'm not sure why you're using a capture group. Are you extracting the last letter of the three uppercase letters? If not, you can simply use:

```
[A-Z]{3}
```

You don't necessarily need groups to use definite quantifiers. :)

EDIT: To prevent more consecutive uppercase letters, you can make use of negative lookarounds:

```
(?<![A-Z])[A-Z]{3}(?![A-Z])
```

`(?<![A-Z])` makes sure there's no preceeding uppercase letter;

`(?![A-Z])` makes sure there's no following uppercase letter.

Consecutive uppercase letters regex

Solution

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