Regex negative lookahead - not preceded by

المعرفة:: Regex الحالة::مؤرشفة المراجع:: https://stackoverflow.com/a/7317116

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A zero-width negative lookahead:

• Line starts with title then whatever not followed by space

^title:(?! )(.*))

The (?!...) part means “only match if the text following (hence: lookahead) this doesn’t (hence: negative) match this. But it doesn’t actually consume the characters it matches (hence: zero-width).

There are actually 4 combinations of lookarounds with 2 axes:

• lookbehind / lookahead : specifies if the characters before or after the point are considered
• positive / negative : specifies if the characters must match or must not match.