Regex To Check If A String Is All Uppercase (Or Lowercase)

A regular expression to check if a string is all uppercase (or lowercase) letters.

Uppercase

/^[^a-z]*$/

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Matches:

• REGEX
• REGEXPATTERN
• ABCD

Non-Matches:

• regex
• regexpattern
• RegexPattern

Lowercase

/^[^A-Z]*$/

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Matches:

• regex
• regexpattern
• RegexPattern

Non-Matches:

• REGEX
• REGEXPATTERN
• ABCD

See Also:

• Regular Expression For Uppercase Letters
• Regex To Check If The First Letter Is Uppercase

Expression Flags

Flags	Description
i	Ignore case sensitive.
g	Allows global search.
m	Allows multiline search.