Now, you know how to print something on the screen and not just that, you also know about the different data types available in Python and how to use them. Let’s move forward with this chapter and learn a new Python concept.
Till now, we have assigned values to variables in the code. However, there can be times when we want the user to enter the value which has to be assigned to a variable. Take an example of a calculator in which the user enters the values to be added or subtracted.
input() function is used to take input from the user. So, let’s see how to take values entered by the user.
name = input()
The statement in the above code will read the value entered by the user (xyz) and will assign it to the variable
We can also print a message on the screen while asking the user for input by passing that message to the
name = input("What is your name >>>")
In this example, the message “What is your name >>>” will get printed on the screen and the value entered by the user after that will be assigned to the variable
name. The message displayed on the screen while taking input is helpful to understand what type of input the user is expected to enter. Therefore, it is a good practice to display such messages while taking input.
Let’s look at some other examples.
print("Enter your name") x = input() y = input("age >>>") #age>>> will be printed before input print("Your name is",x,"and","and your age is",y)
print("Enter your wish") wish = input() print("May your wish come true!")
What does input() do?
x = input(">>>") print(x)
If the user enters 10, then the first statement is equivalent to
x = '10'.
We gave 10 to
input(). You can think that
input() becomes 10. So,
x = input() will be equivalent to
x = 10 after the input is given.
Taking String Input in Python
By default, any input entered by the user is of type string.
num = input() print(type(num))
As you can see, the user entered a number 10 as input but its type is str. Therefore, any input entered by the user is always read as string.
Taking Integer Input in Python
We just saw that input is always read as a string. So what if we want to read an integer?
We can do this by converting the string input to int using the
x = int(input("Enter an integer >>>")) print ("You have entered", x)
int() changes a string to an integer. For example,
int('12') will give us an integer 12.
In the above example, we are taking the input from the user as a string with the
input() function and then we are using
int() to change it to an integer. So, if a user enters 12, then
input() will become '12' (a string) and the above statement
int(input()) will become
int('12') and we will get 12 as an integer.
We can also break the above example in one more step to understand better.
x = input("Enter an integer >>>") y = int(x) print("You have entered", y)
Here, we passed 12. Thus,
'12' and then
int(x) turned it into an integer.
Taking Float (Decimals) Input in Python
Similar to taking input of integers, we can use
float() to take an input from the user and change it to a float.
x = float(input()) print(x) print(type(x))
It is similar to taking input of integers. We entered 12.32 to
input() which returned
'12.32' (a string). Thus, the expression
float('12.32'), and that gave us a float
Let your computer do some maths for you
import math print(math.sin(30)) print(math.cos(10)) print(math.pow(2,3))
import math → This will include Python's inbuilt directory 'math'. It contains many mathematical functions for our use. import is a keyword used to
import any available directory.
math.sin() computes sine of a given angle.
math.cos() computes cosine of a given angle.
a raised to the power of
We have imported 'math' and these functions are provided by it, so 'math.sin()' can be understood as the sin() function from the 'math' directory.
Checkout python's official documentation for more functions available in math.