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Python | Different ways to define and call user-defined functions

Python function definitions and calling: Here, we are going to learn the different ways to declare define and call a function.
Submitted by Pankaj Singh, on October 11, 2018

1) Define first and then call

#Function Defination
def hi():
    print("Hi")

#Function Calling
hi()

Output

Hi

2) Calling before define – but it will not work

# Function Calling
hi()

# Function Definition
def hi():
    print("Hi")

Output

    hi()
NameError: name 'hi' is not defined	

3) Function calling inside another function

def main():
    hi()

def hi():
    print("Hi")

main()

Output

Hi

4) Define main as starting point

def main():
    hi()

def hi():
    print("Hi")

if __name__=="__main__":
    main()

Output

Hi