Alex <[EMAIL PROTECTED]> wrote: > Hye, > > I was just wondering what is the difference between > > >> if my_key in mydict: > >> ... > > and > > >> if mydict.has_keys(my_key):
Mis-spelled (no final s in the method name). > >> ... > > I've search a bit in the python documentation, and the only things I > found was that they are "equivalent". Semantically they are, but `in' is faster, more concise, & readable. > But in this (quiet old) sample ( "http://aspn.activestate.com/ASPN/ > Cookbook/Python/Recipe/59875" ), there is difference between the two > notation. What that example is pointing to as "wrong way" is a NON-equivalent approach that's extremely slow: if my_key in mydict.keys(): The call to keys() takes time and memory to build a list of all keys, after which the ``in'' operator, having a list as the RHS operand, is also quite slow (O(N), vs O(1)!). So, never use that useless and silly call to keys() in this context! Alex -- http://mail.python.org/mailman/listinfo/python-list
