Question

This is a piece of my code…

def contactMaster(data="",url= str(chosenMaster)+"todolist"):
    print "url: "+url

It prints only “todolist” instead of “http://www.mysite.com/blah/1234/todolist”

Why isn’t it working??

Answer 1

Default arguments are evaluated when the function is defined not when it is executed. So if chosenMaster is empty when Python defines contactMaster, it will print only todolist.

You need to move str(chosenMaster) into the function.

See Default Argument Values in the Python Tutorial for more info. The example there is:

The default values are evaluated at the point of function definition in the defining scope, so that

i = 5

def f(arg=i):
    print arg

i = 6
f()

will print 5.