Vim negative lookahead and negative look behind in one regular expression
regex, vim
Solution
Got it
\([>]\)\@<!\<\(4[25]\|21\)\( days\)\@!
or
\v([>])@<!<(4[25]|21)( days)@!
As you can see, syntax for lookaround is different in vim and you have more than one mode for searching with regular expressions I generally use `nomagic` and `very magic`
Take some time to see the help of magic modes: `:help /magic`
EDIT
Now it includes 45 and 21 too
Problem
I am trying to convert this regular expressions from sublime text into one I can use in vim: `(?<![>\w\d])(42|45|21)\s(?!days)` I would like to match 42, 45, and 21 where they are not immediately proceeded by a <, a word character, or a digit and are not followed by the word days. In example, I want to find the 42 in this: `This is a reference to chapter 42 in the book.` But not this: `This is a reference to chapter <a href="#">42</a>.` Or this: `This is a reference to chapter <a href="#">42 section 35</a>.` Or this: `This book took 42 days to write.` I am fairly new to regular expressions in general and super new to vim, so please forgive me if this is a malformed regex to begin with.