What you’ve learned?
What are loops and how it reduce the effort of reducing instructions
What is for loop and how to iterate with it
What is range() function and how to iterate through lists
How to iterate with while loop
Functions
• A function is a group of statements that together perform a task
• Functions are one way to reuse code—you can use functions in
your programs again and again.
Parts of a Function
• A function has three parts: a name, parameters, and a body.
Here’s an example of a simple function:
>>> def testfunc(myname):
print('hello %s' % myname)
Parts of a Function
• A function has three parts: a name, parameters, and a body.
Here’s an example of a simple function:
>>> def testfunc(myname):
print('hello %s' % myname)Def is a python keyword
provided for programmers to create a
python function
Parts of a Function
• A function has three parts: a name, parameters, and a body.
Here’s an example of a simple function:
>>> def testfunc(myname):
print('hello %s' % myname)
Testfunc is the name of the function. We can give any name for the
function as per our convenience
Parts of a Function
• A function has three parts: a name, parameters, and a body.
Here’s an example of a simple function:
>>> def testfunc(myname):
print('hello %s' % myname)
Myname is called as the parameter of the function. A parameter is a variable that exists only while a function is being used.
Parts of a Function
• A function has three parts: a name, parameters, and a body.
Here’s an example of a simple function:
>>> def testfunc(myname):
print('hello %s' % myname)
This space indicates that we are going to start a block. Which is obviously the body of the function. And in our body there is only one statement which is print()
Calling a function
>>> def testfunc(myname):
print('hello %s' % myname)
>>> testfunc('Mary')
Function body or definition
Calling the function
Calling a function
>>> def testfunc(myname):
print('hello %s' % myname)
>>> testfunc('Mary')
Function body or definition
Calling the function
Output
hello Mary
Calling a function
>>> def testfunc(myname):
print('hello %s' % myname)
>>> testfunc('Mary')
The value Mary will be assigned to the variable myname during the function call
Output
hello Mary
Returning a value
• A function is often used to return a value, using a return
statement. For example, you could write a function to calculate
your average mark
>>>def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=averageMark(35,35,50)
>>>print(a)
40
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>> a=averageMark(35,35,50)
print(a)
Function body or definition
Calling the function
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=averageMark(35,35,50)
print(a)
If you call the function averageMark() it will calculate and return the average
Calling the function
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=averageMark(35,35,50)
print(a)
This is where we call the function averageMark(). We pass three parameters 35,35,50 during function call
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=averageMark(35,35,50)
print(a)
This is where we call the function averageMark(). We call it with three parameters 35,35,50
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a = averageMark(35,35,50)
print(a)
It calculate and returns the average value. Ie 40
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a = averageMark(35,35,50)
print(a)
So this selected potion will be replaced with the returned value. Ie 40
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=40
print(a)
So variable a will be having a value 40
Example Returning a value
>>> def averageMark(science,english,maths)
return (science+english+maths)/3
>>>a=40
print(a) Output40
Exercise !
• Create a function named “MyDetails()” , calling which will print all the
details about you
• Create a function to calculate the square of any number passed into it
• Crate a function that will return the square of any number passed in to it
What you’ve learned?
What is function ? And how it will help you to reuse your code
What is parameters? How to pass parameter in to a function
How to return a value from a function