The caret “^” and the “&” operators are used for matching the beginning of a string, and also for the end of a string shown below:

matching =/[a-e]$/

The script would look for similar letters between “a” and “e” respectively including the end of the string. To search for a letter inside a string:

[A-Z] all uppercase letters
[a-z] all lowercase letters
[0-9] all digits(numbers)

To restrict the range, say to look for only the letters between “a” and “e”, you write it as [a-e] combined with the caret operator shown below:

[^A-Z] all other characters except uppercase letters
[^a-z] all other characters except lowercase letters
[^A-Za-z] no letters, whether upper or lower case