Function in Python | with an Example
Function in Python with an example | Everything you need to know about functions in python.
Function in Python
- A function is a group of logically related statements
- Grouped into one block of statement
- Re-usable
As we already know, Python gives you many
built-in functions like print (), etc. but we can also create our own
functions. These functions are called user-defined functions.
Defining
a Function
You can define functions to provide the
required functionality. Here are simple rules to define a function in Python.
·
Function blocks begin with the
keyword def followed by the function name and parentheses (( )).
·
Any input parameters or arguments should be placed
within these parentheses. You can also define parameters inside these
parentheses.
·
The code block within every function starts
with a colon (:) and is indented.
· The statement return [expression] exits a function, optionally passing back an expression to the caller. A return statement with no arguments is the same as a return of none.
Calling a Function:-
Method using the parameter:
Naming convention for
method:
·
Method name should be in small case
· If the method name having two words separate the method name with an underscore (_) to improve readability.
·
All the identifiers rules are applicable.
*args
are mostly used in function definitions. *args allow you to pass a variable
number of arguments to a function. What variable means here is that you do not
know beforehand how many arguments can be passed to your function by the user
so in this case, you use this keyword. args is used to send a non-key worded variable-length
argument list to the function. Here’s an example to help you get a clear idea:
Return Type of Function:
Case-1:
- The default data type of function is none.
- · If the user is not returning any value then python will return none statement
- · It is always best practice to write a return statement at the end of the function otherwise the statements which are present after the return statement will not be executed.
- · User also can return his own value
Case-2
Question: Can we have multiple return statements?
Case-3
Case-4
Multiple values we can
return into a single line:-
Case-5
Boolean value also we can
return:-
Default value store in the form of a tuple:
By default, if only one return value python will return the default value as in the form of a tuple.
In function, we can return
list and string as well.
Recursion in Python:-
We know that in Python, a function can call other
functions. It is even possible for the function to call itself. These types of the construct are termed recursive functions.
1. Only the outer function will execute because the inner function is not called
2. We can have the same function name as the outer and inner
3. Call both inner and outer function
4. When an inner function is not called
5. Recursive Call :
The above code executes for an infinite loop because the outer function is called repeatedly on its own.
Question:-Write a python
program to find factorial of a number
Note:- One function can have multiple return statements but it should be aligned with the condition.
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