Make brain hurt fewer

Useful regular expressions

** Look arounds **

Positive lookahead: q(?=u) // find q followed by u
Negative lookahead: q(?!u) // find q not followed by u
Positive lookbehind: (?<=a)b // find b preceeded by a. CANNOT BE VARIBLE LENGTH
Negative lookbehind: (?<!a)b // find b not preceeded by a. CANNOT BE VARIBLE LENGTH

** Atomic grouping **



<!-- replace ' or ’ with HTML apostrophe -->

Find: (?<=\w)'|’(?=\w)
Replace: &#8217;

<!-- find repeated words -->

Find: \b([\w']+)\s\1

<!-- replace CSS #xxxxxx with #xxx -->

Find: #([\da-f])\1([\da-f])\2([\da-f])\3\b
Replace: #$1$2$3