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# Regex for vowels

An alphabet is a unit of information that represents a single letter i.e., from a-z or A-Z. A vowel is an alphabet that contains vowels i.e., these 5 alphabets a,e,i,o,u. In this article let's understand how we can create a regex for vowel and how regex can be matched for a given vowel.

Regex (short for regular expression) is a powerful tool used for searching and manipulating text. It is composed of a sequence of alphabets that define a search pattern. Regex can be used to find patterns in large amounts of text, validate user input, and manipulate strings. It is widely used in programming languages, text editors, and command line tools.

# Structure of a vowel

The string should have the following criteria and structure-

• a vowel is a unit of information that represents a single letter a, e, i, o, u and its capitalized letters

# Regex for checking if vowels is valid or not

Regular Expression for a single vowel-

/^[aeiou]$/gmi  Regular Expression for one or more vowels- /^[aeiou]+$/gmi


Test string examples for the above regex-

Input StringMatch Output
bjqwmatches
12Gdoes not match
ATOZdoes not match
qwrtymatches
aeioudoes not match

Here is a detailed explanation of the above regex-

/^[aeiou]+$/gmi ^ asserts position at start of a line Match a single character present in the list below [aeiou] + matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy) aeiou matches a single character in the list aeiou (case insensitive)$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and \$ to match the begin/end of each line (not only begin/end of string)
i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])


Hope this article was useful to check if the string is a valid vowels or not.