Question: I am trying to match a string that has the form:

```
abcd:vxyz

```

That is: 4 chars followed by a colon then followed by three (or maximum) 4 chars.

I want to do case INSENSITIVE matches.

Can anyone help with the pattern?

Answer: 
```
/^[a-z]{4}:[a-z]{3,4}$/i

```

........
The following regex should work:

```
"^[a-zA-Z]{4}:[a-zA-Z]{3,4}$"

```

The {4} part indicates that it should match exactly four copies of the previous symbol, which can be any character between 'a' and 'z', as well as 'A' and 'Z', inclusive.

The {3,4} part creates a range of copies between 3 and 4 inclusive, while the '^' symbol indicates that it should start at the beginning of the given string and the '$' sign indicates that it should end at the end of the given string.