question about speed of sequential string replacement vs regex or

Xah Lee xahlee at gmail.com
Wed Sep 28 11:28:38 CEST 2011


curious question.

suppose you have 300 different strings and they need all be replaced
to say "aaa".

is it faster to replace each one sequentially (i.e. replace first
string to aaa, then do the 2nd, 3rd,...)
, or is it faster to use a regex with “or” them all and do replace one
shot? (i.e. "1ststr|2ndstr|3rdstr|..." -> aaa)

let's say the sourceString this replacement to be done on is 500k
chars.

Anyone? i suppose the answer will be similar for perl, python, ruby.

btw, the origin of this question is about writing a emacs lisp
function that replace ~250 html named entities to unicode char.

 Xah



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