Positive Lookahead: Peeking Ahead
Lookaheads are zero-width assertions. They peek forward, check for a match, and then return to the position where they started. The syntax is (?=...).
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LearnStep 1 of 3
Understanding Lookahead
Learning Objectives
- •Understand zero-width assertions
- •Use positive lookahead
- •Create password validation patterns
Lesson Outline
LearnStep 1/3
Understanding Lookahead
python
Notice that the match is only "Windows", not "Windows 11". The lookahead checks but doesn't consume.