Python Functions
A function is a block of code which only runs when it is called.
You can pass data, known as parameters, into a function.
A function can return data as a result.
Creating a Function
In Python a function is defined using the def keyword:
Example
def my_function():
print("Hello from a function")
Calling a Function
To call a function, use the function name followed by parenthesis:
Parameters
Information can be passed to functions as parameter.
Parameters are specified after the function name, inside the parentheses. You can add as many parameters as you want, just separate them with a comma.
The following example has a function with one parameter (fname). When the function is called, we pass along a first name, which is used inside the function to print the full name:
Example
def my_function(fname):
print(fname + " Refsnes")
my_function("Emil")
my_function("Tobias")
my_function("Linus")
Run example »
Default Parameter Value
The following example shows how to use a default parameter value.
If we call the function without parameter, it uses the default value:
Example
def my_function(country = "Norway"):
print("I am from " +
country)
my_function("Sweden")
my_function("India")
my_function()
my_function("Brazil")
Run example »
Return Values
To let a function return a value, use the return
statement:
Example
def my_function(x):
return 5 * x
print(my_function(3))
print(my_function(5))
print(my_function(9))
Run example »
