In yesterday's entry , I mentioned that Iwas surprised by the relative performances of my three reimplementationsof the .find() string method.

The src[i:].startswith(sub) version was the slowest, and why isobvious in hindsight: it's summed up clearly in the first bit, where wecreate a big new string ( src[i:] ) on every iteration of the loop. Nowonder it's slow; creating big strings is slow in general, because

As a followup to my entry on the two sorts of languages , I decided to actually tryimplementing the string .find() method in Python to see how muchslower it is. The Python version uses the brute force C style approach,roughly:

for i in range(0, len(src)-len(sub)+1):    if src[i:i+len(sub)] == sub:       return ireturn -1

I actually did three versions, each with a different