Question

What regular expression returns all sets of lowercase alphabetical characters?

Answer 1

Since the options are not given, I am giving an assumed answer.

The answer could be - [a-z]

A regular expression is a way that specifies a pattern of a particular set of words or characters in a text which can be applied to the variable inputs.

When a search has been narrowed down to the lower case alphabetic characters, a character class command search can be used. It is important to notify all the lower case characters in between the brackets. There are shorthand notations to make this easier.

So, the command [a - z] is used to depict the command for the lower case characters and the '-' indicates the range.

Answer 2

A regular expression, often shortened to “regex” or “regexp”, is a way of specifying a pattern (a particular set of characters or words) in text that can be applied to variable inputs . Grep is a tool used to search for specified patterns within text input using regular expressions. 

Character Sets match one or more characters in a single position. Modifiers specify how many times the previous character set is repeated.

A regular expression which few people has written as "/^[a-zA-Z]$/i" is not correct because at the last they have mentioned /i which is for case-insensitive and after matching for the first time.