03-input.md

Take Input from the User

Video link: https://youtu.be/DRBybZ6hsY0

In this video, we learned to take input from the user.

Programs in the Video

• Take input from the user
• Printing message before input
• Trying to take numeric input
• Print data type of integers and floating-point numbers
• Convert strings to integers
• Convert non-numeric strings to numbers

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input() Function

We use the input() function to take input from the user.

Take Input from the User

# Take user input

name = input()
print(name)

Output

Felix
Felix

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Printing Message Before Input

We can pass a string message inside input() to make our program descriptive.

# Displaying prompt message before taking input

name = input("Enter name: ")
print(name)

Output

Enter name: Felix
Felix

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Trying to take numeric input

The input() function always takes input in the string format. We can check this by using the type() function.

# Print the type of input.

number = input("Enter a number: ")
print(type(number))

Output

<class 'str'>

<class 'str'> means it's a string.

---

Print data type of integers and floating-point numbers

# print type of integers and floats

number1 = 5
print(type(number1))

number2 = 5.5
print(type(number2))

Output

<class 'int'>
<class 'float'>

---

Convert strings to integers and floats

We cannot directly take numeric inputs using the input() function. However, we can convert strings to integers and floats using the 'int()' and 'float()' functions respectively.

Convert strings to integers

number = input("Enter a number: ")

# convert numeric string to integer
number = int(number)

print(type(number))

Output

<class 'int'>

Here, we have converted number in string format to integer.

We can also write this above program as:

# take input and convert it to int
number = int(input("Enter a number: "))

print(type(number))

Output

<class 'int'>

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Convert strings to floats

Similary, we can use float() to convert a string to a floating-point number.

# take input and convert it to float
number = float(input("Enter a number: "))

print(type(number))

Output

<class 'float'>

---

Convert non-numeric strings to numbers

We can only convert numeric strings (string in number format) to numbers. If we try to convert non-numeric strings to numbers, we will get an error.

# take input and convert it to float
number = float(input("Enter a number: "))

print(type(number))

Output

Enter a number: Punit
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ValueError: could not convert string to float: 'Punit'