Regex To Determine If A String Has All Unique Characters

A regular expression that determines if a given string has all unique (none repeating) characters. This is something needed when doing reports or analyses of what is in a string.

/^(?:([A-Za-z])(?!.*\1))*$/g

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Matches:

• abcde
• com
• net

Non-matches:

• regex
• pattern
• aabbcc

See Also:

• Regular Expression To Check For Repeating Numbers
• Regex To Match Characters Repeated More Than A Specified Number Of Times