Making your own functions

We can define new custom functions by giving a name and the sequence of statements that execute when the function is called. Once we define a function, we can reuse the function over and over throughout our program. For eg,

def print_name():
    name = "Cloudxlab"        
    print("My name is", name)

It assigns "Cloudxlab" to the variable name and then prints it.

def is a keyword that indicates that this is a function definition. The name of the function is print_name.
The rules for function names are the same as for variable names: letters, numbers and some punctuation marks are legal, but the first character can't be a number.
You can't use a keyword as the name of a function, and you should avoid having a variable and a function with the same name.
The empty parentheses after the name indicate that this function doesn't take any arguments. Later we will build functions that take arguments as their inputs.
The first line of the function definition is called the header; the rest is called the body. The header has to end with a colon and the body has to be indented. By convention, the indentation is always four spaces. The body can contain any number of statements.

Try printing the type of print_name and see the result,

print(type(print_name))

The syntax for calling the new function is the same as for built-in functions:

print_name()

We can call a function inside another function or within the same function (called recursion)
The statements inside the function do not get executed until the function is called.

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Foundations of Python

Making your own functions

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