I tried to use re.findall('^(?!a)b', 'xyzabbcdebt') to select all b not starts with a.
I expect to have ['b', 'b'].
However, it gives an empty array.
What is the correct regex?
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Chan
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2Use a lookbehind, `r'(?<!a)b'` – Wiktor Stribiżew Dec 06 '19 at 09:42
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Can you explain? – Chan Dec 06 '19 at 09:43
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1`(?!a)` is a lookahead, you need a lookbehind. From the linked thread: "*Where `(?<!x)` means "only if it doesn't have "x" before this point".*" – Wiktor Stribiżew Dec 06 '19 at 09:43