Python- Input function

Good Morning Boys.

Welcome to the fourth session of the online classes for Python Programing.
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By the end of this session, you will be able to understand 

• the purpose and syntax of the input( ) function
• working of the input( ) function                 
• Understand and apply the concept of TYPECASTING.

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Lets see whether the following terms are clear to you or not ?
1. Identifier
2. Comment

• inline comment
• multiline comment

Doubts if any, must be shared now. I am waiting.🙏 

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Having revised yesterday's content. Lets move ahead.

The topic of the discussion today is the INPUT function in PYTHON- input( )

Taking input in Python

Developers often have a need to interact with users, either to get data or to provide some sort of result. Most programs today use a dialog box as a way of asking the user to provide some type of input. While Python provides us with two inbuilt functions to read the input from the keyboard.

• raw_input ( prompt )
• input ( prompt )

We will limit our discussion to INPUT( ) 

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Syntax

input(prompt)

Parameter Values

Parameter	Description
prompt	A String, representing a default message before the input.

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More Examples

Example

Use the prompt parameter to write a message before the input:

x = input('Enter your name:')
print('Hello, ' + x)

If the user enters "Geeta" as the name, the OUTPUT will be: 

Enter your name:

Hello, Geeta

input ( ) : This function first takes the input from the user and then evaluates the expression, which means Python automatically identifies whether user entered a string or a number or list. 

If the input provided is not correct then either syntax error or exception is raised by python. For example –

# Python program showing  # a use of input()    val = input("Enter your value: ") print(val)

Output:


How the input function works in Python :

• When input() function executes program flow will be stopped until the user has given an input.
• The text or message display on the output screen to ask a user to enter input value is optional i.e. the prompt, will be printed on the screen is optional.
• Whatever you enter as input, input function convert it into a string. if you enter an integer value still input() function convert it into a string. You need to explicitly convert it into an integer in your code using typecasting.

 TYPECASTING- The process of converting the value of one data type (integer, string, float, etc.) to another data type is called TYPECASTING

Example 

n=int(input("Enter your age"))

Here 

--> the user is shown the message -"Enter your age" and is prompted to enter value for age. 

--> Whatever he enters is typecasted  to integer.

EXERCISE

Write statements in PYTHON to do the following:

1. Accept a number from the user . Display an appropriate message .

2. Accept a name from the user . Display an appropriate message .

3. Accept the name and age of the user. Display appropriate messages.

4. Accept two numbers from the user. Display appropriate messages before taking the input.

5. Accept a number from the user and typecast it to float.