I would like to define my function f(x,a) in which the value of 'a' changes, so that every time I call f(x,a), the value of 'a' will be different. So far the following code serve the purpose:
a=0
def f(x):
global a
a=a+1
return a+x**2
In this case, everytime f(x) is called, the value of a is changed as well. I am wondering if there are any other ways to realize the results? Thank you.
You can take advantage of using a mutable default value (normally this is a gotcha that trips people up, I never thought I would use it on purpose):
def f(x, a={"value":0}):
a["value"] += 1
#Do other stuff
But since you are trying to encapsulate a piece of functionality with some data you would probably be better off creating a new class:
class Foo:
def __init__(self):
self.a = 0
def f(self, x):
self.a += 1
return x + self.a
foo = Foo()
foo.f(0) # 1
foo.f(0) # 2
You should pass a to f each time you call it instead of using a as a global variable. Something like
def f(x, a):
# your code
A full example
def f(x, a):
a = a + 1
return a + x ** 2
if __name__ == "__main__":
x = 1
a = 2
print f(x, a)
# output 4
a and pass it to f. e.g. a += 1, then call f(x, a). I would suggest you learn some basics about Python function.