I am trying to split a string in python before a specific word. For example, I would like to split the following string before \"path:\".
using a regular expression to split your string seems a bit overkill: the string split() method may be just what you need.
anyway, if you really need to match a regular expression in order to split your string, you should use the re.split() method, which splits a string upon a regular expression match.
also, use a correct regular expression for splitting:
>>> line = 'path:bte00250 Alanine, aspartate and glutamate metabolism path:bte00330 Arginine and proline metabolism'
>>> re.split(' (?=path:)', line)
['path:bte00250 Alanine, aspartate and glutamate metabolism', 'path:bte00330 Arginine and proline metabolism']
the (?=...) group is a lookahead assertion: the expression matches a space (note the space at the start of the expression) which is followed by the string 'path:', without consuming what follows the space.