Last Updated on October 18, 2023 by Ankit Kochar
The input function in Python is a powerful tool for interacting with users and collecting data from the keyboard during program execution. Whether you’re creating a simple command-line application or building a complex software system, the input() function allows you to gather user input and make your programs more interactive and dynamic. In this article, we’ll explore the Python input function in detail. We’ll discuss how to use it to obtain user input, store the input as variables, and perform various operations based on that input. Additionally, we’ll cover best practices, error handling, and security considerations when using input() to ensure that your Python programs are user-friendly and robust.
Input Function in Python
The input function is a built-in function in Python that allows developers to read data from the user. The input function in python reads the input as a string, which can then be converted into other data types, such as integers, floating-point numbers, or booleans.
Syntax of Input Function in Python
The syntax of the input function in python is straightforward. It takes a single argument, which is the message to be displayed to the user.
input([prompt])Parameters of Input Function in Python
It will take only a single argument which is optional.
*prompt: it is a string that is written with respect to standard output without going into a new line.
Return Type of Input Function in Python
The input() method reads a line from the input (often from the user), removes the terminating newline to turn the line into a string, and then returns the string.
An EOFError exception is raised if EOF is read.
Examples of Input Function in Python
We will learn in brief about input() function in detail with the help of some examples.
Example 1 of input() Function in Python: taking the Name and ID of the user as the input from the user and printing it.
Here we will look at the example that will show how to take input from the user and print it.
Code Implementation
name = input("Please Enter Your Name: ")
id= input("Please Enter Your Employee ID: ")
print("Name & Id: ", name, id) Output
Please Enter Your Name: Naman
Please Enter Your Employee ID: 4568974
Name & Id: Naman 4568974Explanation of the above code
When you run this code, it will prompt the user to enter their name and age in the command line interface. The input() function is used to get the user’s input as a string.
The code then stores the user’s input in the name and age variables, and finally prints out a message that combines the user’s name and age using the print() function.
Example 2 of input() Function in Python: Taking two numbers from the users as input and then printing the multiplication of those numbers.
Now we will see the code and implementation of the above-mentioned example.
Code Implementation
# Ask the user for two integers
num1 = int(input("Enter the first integer: "))
num2 = int(input("Enter the second integer: "))
# Multiply the two numbers
result = num1 * num2
# Print the result
print("The product of", num1, "and", num2, "is", result) Output
Enter the first integer: 25
Enter the second integer: 14
The product of 25 and 14 is 350Explanation of the above example
In the above code, we start by using the input() function to ask the user for two integers. The input() function takes a string as an argument, which is displayed to the user as a prompt. The user can then enter a value, which is returned by the input() function as a string.
Since we want to perform multiplication on the input values, we need to convert them to integers using the int() function. We assign the converted input values to the variables num1 and num2.
Next, we perform the multiplication operation on the two numbers by using the * operator. We assign the result of the multiplication to the variable result.
Finally, we print out the result using the print() function. We use string concatenation to construct a message that includes the original input values as well as the result. The print() function can take multiple arguments, which are separated by commas. In this case, we’re using commas to separate the different parts of the message.
Example 3 of input() Function in Python: Taking two lists as input from the users and appending them and printing the result.
The implementation with code and output of the above example is explained below:
Code Implementation
list1 = []
list2 = []
# Taking input for the first list
input_list1 = input("Enter elements of the first list separated by space: ")
list1 = input_list1.split()
# Taking input for the second list
input_list2 = input("Enter elements of the second list separated by space: ")
list2 = input_list2.split()
# Appending the second list to the first list
for element in list2:
list1.append(element)
# Printing the appended list
print("Appended List: ", list1) Output
Enter elements of the first list separated by space: 9 8 7 6 5
Enter elements of the second list separated by space: 4 3 2 1 0
Appended List: ['9', '8', '7', '6', '5', '4', '3', '2', '1', '0']Explanation of the above code
In this example, we start by creating two empty lists, list1 and list2. We then use the input() function to prompt the user to enter elements for the first list, and store the input in the variable input_list1. Similarly, we prompt the user to enter elements for the second list and store the input in the variable input_list2.
Since the input() function returns a string, we need to use the split() method to split the string into a list of separate elements. We then assign the resulting lists to list1 and list2.
Next, we use a for loop to iterate over the elements in list2 and append each element to list1 using the append() function.
Finally, we print the appended list using the print() function.
Working of the Input Function
When the input function in python is called, it displays the message provided as an argument to the user. The user can then type in the input and press the enter key. The input is then returned as a string. The input function in python blocks the program’s execution until the user provides the input and presses the enter key.
Handling User Input
The input function in python can accept any type of input from the user, such as strings, numbers, or booleans. However, the input is always treated as a string. If the input is not converted into the appropriate data type, it will cause errors.
Converting Input into other Data Types
To convert the input into other data types, such as integers or floating-point numbers, we can use the built-in conversion functions, such as int(), float(), or bool().
Handling Exceptions
When converting the input into other data types, it is essential to handle exceptions. If the input provided by the user cannot be converted into the desired data type, it will cause an error.
Default Value
The input function also allows us to provide a default value, which will be used if the user does not provide any input.
Conclusion
The input function in Python is a versatile tool for creating interactive programs that can gather user input and respond dynamically to user actions. Whether you’re building a simple calculator, a text-based game, or a data collection tool, understanding how to use input() effectively is a valuable skill.
In this article, we’ve explored the various aspects of the input() function, including how to prompt users for input, handle different data types, and manage potential errors. We’ve also discussed best practices, such as validating user input and ensuring that your programs are user-friendly and secure.
As you continue to develop Python applications, keep in mind that the input() function is a fundamental building block for creating dynamic and engaging software. By mastering its usage, you can enhance the interactivity and user experience of your Python projects.
Frequently Asked Questions Related to Input Function in Python
Here are some FAQs related to Python input functions.
1. How does the input() function work in Python?
The input() function displays a prompt to the user, waits for them to enter text from the keyboard, and returns the entered text as a string. You can then store and manipulate this input in your program.
2. Can I use the input() function to collect numerical input from the user?
Yes, you can collect numerical input from the user using input(). However, you’ll need to convert the input to the desired data type (e.g., int or float) using type casting.
3. How do I display a custom prompt with the input() function?
You can include a custom prompt by passing a string argument to the input() function. For example, user_input = input("Enter your name: ") will display "Enter your name: " before waiting for input.
4. What should I do to ensure that user input is valid and safe?
It’s essential to validate and sanitize user input to prevent unexpected behavior and security vulnerabilities. You can use techniques like input validation (checking if the input meets certain criteria) and input sanitization (cleaning the input of potentially harmful characters).
5. How can I handle exceptions when using the input() function?
You can use a try-except block to catch exceptions that may arise when using input(), such as ValueError if the user enters invalid data. This allows you to provide user-friendly error messages and gracefully handle unexpected input.
6. Are there any security concerns when using the input() function?
Yes, there can be security concerns, especially if the input is used in operations like file access or database queries. To mitigate security risks, consider using input validation, input sanitization, and parameterized queries when interacting with external resources.