On 1月13日, 下午8时32分, Hrvoje Niksic <[EMAIL PROTECTED]> wrote: > Use lambda when it works better for you, the speed difference is > marginal in practice anyway. itemgetter is not (and was never > intended to be) a general substitute for functions, as you've > discovered. > > The marginal speed difference between itemgetter and an explicit > lambda that does the subscripts is a consequence of itemgetter being > written in C, meaning it avoids the creation of a Python stack frame, > etc. Combining int(...) with this operation requires coding the key > function in Python, which removes itemgetter's advantage. In other > words, you cannot retain itemgetter's speed advantage with more > complex keys. If the sorting performance is a problem for you, please > give more details about what you're doing -- there might be better > ways to speed up the code.
Fredrik and Hrvoje, thanks for the reply, here the sorting performance is not a big problem for me. the text file is just several hundred line, each line include several item separated by space. I'll run the script each week or month, just 1 second to get the result,so maybe stick to lambda here is just fine. -- http://mail.python.org/mailman/listinfo/python-list
