On Aug 23, 7:59 am, smith jack <thinke...@gmail.com> wrote: > i have heard that function invocation in python is expensive, but make > lots of functions are a good design habit in many other languages, so > is there any principle when writing python function? > for example, how many lines should form a function?
My suggestion is to think how you would test the function, in order to get 100% code coverage. The parts of the function that are difficult to test, those are the parts that you want to pull out into their own separate function. For example, a block of code within a conditional statement, where the test condition cannot be passed in, is a prime example of a block of code that should be pulled out into a separate function. Obviously, there are times where this is not practical - exception handling comes to mind - but that should be your rule of thumb. If a block of code is hard to test, pull it out into it's own function, so that it's easier to test. -- // T.Hsu -- http://mail.python.org/mailman/listinfo/python-list
