May I know what ?= means in a regular expression? For example, what is its significance in this expression:
(?=.*\d).
Regex ?= Meaning – Understanding Regular Expressions
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May I know what ?= means in a regular expression? For example, what is its significance in this expression:
(?=.*\d).
Best Answer
?=is a positive lookahead, a type of zero-width assertion. What it's saying is that the captured match must be followed by whatever is within the parentheses but that part isn't captured.Your example means the match needs to be followed by zero or more characters and then a digit (but again that part isn't captured).