Python – Read Float from Command Line

Read Float from Command Line

To read floating-point number from command line in Python, we can use input() builtin function. Since, input() function reads a string from standard input, we can use float() function to convert the string to float.

The following is a simple code snippet to read a float into variable x.

x = float(input())

We can also prompt user via input() function.

x = float(input('Enter a float : '))

Examples

Read floating-point number from user

In the following example, we read a float from user into variable x, using input() and float() functions.

Python Program

try:
    n = float(input('Enter a float : '))
    print('N =', n)
except ValueError:
    print('You entered an invalid float')

Output

Enter a float : 3.14
N = 3.14

Now, we shall read two floating-point numbers from user, add them, and print the result to output.

Python Program

try:
    a = float(input('Enter a : '))
    b = float(input('Enter b : '))
    output = a + b
    print('Sum :', output)
except ValueError:
    print('You entered an invalid float')

Output

Enter a : 3.14
Enter b : 1.35
Sum : 4.49

Conclusion

In this Python Tutorial, we learned how to read a floating-point number from user, using input() and float() function.