Regular expression - Negation

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Regular expression is a language that does not have a NOT operator but it has some negative construct

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Construct

Negative Class

^ will negate the class, ie capture until not this characters

Example:

• matches any character other than a, b, or c.

[^abc]1

• matches any single character that is not a lowercase letter from a to z. |

[^a-z]1

• all character except the character p

[^p]*

Negative Look

• Negative lookahead - do we have a pattern ahead
• Negative lookbehind - do we have a pattern behind

See Regexp - Look-around group (Assertion) - ( Lookahead | Lookbehind )

Example:

• Positive lookahead: Capture only if the string has a ?

(?=\?)(.*)