Can you pass functions as arguments?

[bobueland]

I want to calculate f(0) + f(1) + ...+ f(100) over some function f
which I can change. So I would like to create a function taking f as
argument giving back the sum. How do you do that in Python?

 

[Paul Rubin]

I want to calculate f(0) + f(1) + ...+ f(100) over some function f
which I can change. So I would like to create a function taking f as
argument giving back the sum. How do you do that in Python?

You can just pass f as an argument. The following is not the most
concise or general way, it just shows how you can pass a function.

def square(x):
return x**2

def sum100(f): # f(0)+f(1)+...+f(100)
s = 0
for i in xrange(101):
s += f(i)
return s

print sum100(square) # pass square as an argument

 

[Xavier Morel]

I want to calculate f(0) + f(1) + ...+ f(100) over some function f
which I can change. So I would like to create a function taking f as
argument giving back the sum. How do you do that in Python?

Python functions (and classes, and modules) are first-class objects, so
you can use them as regular objects: send them as arguments, generate
and return them from functions, ...

BTW, if your goal is to create that kind of sums of function results, I
think you'd be interested in using both Python's _generators_ and the
built-in function *sum*.

 

[Bengt Richter]

You can just pass f as an argument. The following is not the most
concise or general way, it just shows how you can pass a function.

def square(x):
return x**2

def sum100(f): # f(0)+f(1)+...+f(100)
s = 0
for i in xrange(101):
s += f(i)
return s

print sum100(square) # pass square as an argument
or

338350

which seems to agree with ... s = 0
... for i in xrange(101):
... s += f(i)
... return s
... 338350

or if the OP actually wants the specific function, 338350

Regards,
Bengt Richter

 

[Paul Rubin]

or if the OP actually wants the specific function,
338350

Similarly with generator comprehension, if I have the syntax right:

def sum100c(f): return sum(f(i) for i in xrange(101))