What is first class function in Python

Question

I am still confused about what first-class functions are. If I understand correctly, first-class functions should use one function as an object. Is

Answer 1

No. You are talking about higher-order functions -- refer.

First class functions: If a function can be assigned to a variable or passed as object/variable to other function, that function is called as first class function.

Python, JavaScript and C(pointers) support first class functions.

A simple example (in python):

def square(x): return x * x
def cube(x): return x * x * x

def print_result(x, func):
    """recieve a function and execute it and return result"""
    return func(x)

do_square = square     # assigning square function to a variable
do_cube = cube         # assigning cube function to a variable

res = print_result(5, do_square)   # passing function to another function
print res
res = print_result(5, do_cube)
print res

This program is just for illustration.