Positive Lookbehind (?<=...)
Positive lookbehind asserts that the current position is immediately preceded by a match for the enclosed pattern. The syntax is (?<=...).
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LearnStep 1 of 3
Positive Lookbehind
Learning Objectives
- •Use positive lookbehind
- •Understand fixed-width limitation
- •Extract values after delimiters
Lesson Outline
LearnStep 1/3
Positive Lookbehind
python
Fixed-Width Limitation
Important: In Python's standard re module, lookbehind patterns must have a fixed width.
- Valid:
(?<=abc),(?<=a|b) - Invalid:
(?<=\w+),(?<=a*)