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Functions in Python for Beginners

scdan0624 profile image SCDan0624 ・2 min read

Intro
Similar to other coding languages, functions in python are a blocks of code that will run only after being called. Today we will look at how to create a function and how to use arguments in functions.

Syntax
To call a function you use the def keyword followed by the function name, a parenthesis, and a colon:

def myFunction():
    print("Hello")
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When creating a function in python you must have your block of code after the function name indented:

# correct
def myFunction():
    print("Hello")

# incorrect
def myFunction():
print("Hello")
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Calling a function
To call your function you use the function name, followed by a parenthesis:

def myFunction():
    print("Hello")

myFunction() # prints Hello
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Arguments
Arguments are used to pass information into the function. Arguments are written inside the parentheses of your function. You can name the arguments what you like (similar to a variable) and you can have as many arguments as you like:

def myFunction(name):
    print(f"Hello {name}")

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When we call the function we pass along the information we want used as our argument:

def myFunction(name):
    print(f"Hello {name}")

myFunction("Bobby") # prints Hello Bobby
myFunction("Cade") # prints Hello Cade
myFunction("Scott") # prints Hello Scott
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Keyword Arguments
You can also send your arguments in a key = value syntax in python:

def myFunction(name):
    print(f"Hello {name}")

myFunction(name="Bobby") # prints Hello Bobby
myFunction(name="Cade") # prints Hello Cade
myFunction(name="Scott") # prints Hello Scott
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Default Parameter Value

If you want to have a default parameter value for when a function is called without an argument the following syntax is used:

def myFunction(name="Dan"):
    print(f"Hello {name}")

myFunction("Bobby") # prints Hello Bobby
myFunction() # prints Hello Dan
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Pass Statement
If you have a function written with no code you can use the pass statement to avoid getting an error:

def myFunction():
    pass
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