How to Take User Input in Python 

How to take User Input:?

In Python we can take user input with built-in function input() function. It is library function of Python which is used to take user input through the terminal at run time.

For example,

My_name=input("Enter your name: ")

print("Hello," + My_name + "!")

 Output:

Enter your name: Dr. Manisha. M. More

Hello,Dr. Manisha. M. More!

In above example My-name is a variable which is used to store the value which is entered at run time.

input() function is built-in function or library function in Python used to enter values at run time.  print() is used to display result on screen. In the parenthesis of print() in double quotation Hello string is written and after this + character is used, Here + character combine two strings one is Hello and another is the string stored in My_name variable which is entered at run time.  

Another Example to input values at run time

 

number1=input("Enter first value:")

number2=input("Enter second number:")

print("Entered number is:",number1)

print("Entered second number is:",number2)

a1=input()

print("The third number is",a1)

Output:

Enter first value:200

Enter second number:300

Entered number is: 200

Entered second number is: 300

400

The third number is 400

 

In above example number1 and number2 are two variable used to store two different values. Here the type of variable is not defined, when user enter any value so based on the value it will be considered by the specific type. In above example number1 variable store 200 and it is considered as integer, number2 also have 300 an integer value.

This method is called dynamic typing. Like other programming language variables are not explicitly defined by programmer. If programmer does not mention any type of variable, then type of variable is considered based on values stored in a variable.  

Another variable to input variable by defining the type of variable with the input() function

n1=int(input("Enter first number:"))

n2=float(input("Enter second number:"))

string1=input("Enter your string:")

print("First number is:",n1)

print("Second number is:",n2)

print("The string is:",string1)

Output:

Enter first number:20

Enter second number:30.50

Enter your string:Python programming

First number is: 20

Second number is: 30.5

The string is: Python programming

In this example n1, n2 and string1 variables are declared with its data type with user input function input().  n1, n2 and string1 variables are with its type respectively integer, float and string.  

Another example to take user input and perform addition of two integers.

number1=input("Enter first number")

number2=input("Enter second number")

addition=number1+number2

print("The addition is:" , addition)

Output:

Enter first number20

Enter second number20

The addition is: 2020

In this example two integer user inputs are stored in number1 and number2 variables. Then addition variable is used to perform addition of two numbers. + operator is used to perform addition. But in result instead of addition of two integers two integers are combined and displayed as a result. This is happening because we have not defined the data type of number1 variable and number2 variable and + operator is used. In this case the compiler will consider the type of number1 and number2 is string and it use this + character to combine these two strings.  

This problem is type casting or type conversion. Type casting in Python refers to changing the data type or value of variable from one type to another type.

For example data type conversion from int to string the str() is used. From string to int the int() is used.

So to avoid type casting problem we can define and take user input as follows number1=int(input("Enter first value:"))

number2=int(input("Enter second number:"))

sum=number1+number2

print("The addition of two numbers is:",sum)

sub=number1-number2

print("The subtraction is:",sub)

mult=number1*number2

print("The multiplication is:",mult)

div=number1/number2

print("The division is:",div)

rem=number1%number2

print("The remainder of division is:",rem)

Output:

Enter first value:200

Enter second number:100

The addition of two numbers is: 300

The subtraction is: 100

The multiplication is: 20000

The division is: 2.0

The remainder of division is: 0

 

Another way to work on type casting is as follows,

number1=(input("Enter first value:"))

number2=(input("Enter second number:"))

sum=int(number1)+int(number2)

print("The addition of two numbers is:",sum)

sub=int(number1)-int(number2)

print("The subtraction is:",sub)

mult=int(number1)*int(number2)

print("The multiplication is:",mult)

div=int(number1)/int(number2)

print("The division is:",div)

rem=int(number1)%int(number2)

print("The remainder of division is:",rem)

Output:

Enter first value:200

Enter second number:100

The addition of two numbers is: 300

The subtraction is: 100

The multiplication is: 20000

The division is: 2.0

The remainder of division is: 0

In this example we have used only input function to take user input and by default this input is considered as string. The conversion of string data type to integer data type is done with the int(number1) and int(number2) in the operation of arithmetic operation. Hence string is converted to integer data type.