We already know, Programming is all about processing data. To process the data program needs information as input. It can come in many ways.
Such as,
In this post, we are only interested in getting keyboard input from the user.
Here in this post, we check out, how to receive input from the keyboard. And what is the difference between ‘raw_input()’ and input() function?
Table of Contents
There is function raw_input(). The name itself depicts as it read raw data. It read user data as a string. It does not have the intelligence to interpret the type of data; the user has entered.
name = raw_input('Enter your keyboard input:')
All the data until you press the return key, will be read by this function.
By default, raw_input reads the input data and gives it in the form of a string.
Note: It is an in-built function, so you don’t need to import any external library.
It provides in build function ‘input()’ to read the input from the user.
name = input("What's your Good name? ")
Function input() reads the data from the user as a string and interprets data according to the type of data entered by the user.
If the user enters an integer/float value, Python reads it as an integer/float, unlike the raw_input() function from Python 2.
Note: You can also use input() method in Python 2. If you use the input() function in Python 2, it always read the data as a string and you have to convert it according to your need.
Let’s start exploring it further.
If you want to get input as integer or float in Python 2, you need to convert data into int or float after reading data using raw_input().
mode=int(raw_input('How old are you?:'))
As we are taking input from the user, we can not ensure if the given user input value type is a numeric data type (float or int) or not.
So it is good practice to catch the error using try and except.
try:
mode=int(raw_input('Keyboard Input:'))
except ValueError:
print("This is not a number.")
Another way is you can check the data type of the input using isdigit().
mode = raw_input('Keyboard Input:')
if(mode.isdigit()):
print("Number is an integer.")
else:
print("Number is not an integer.")
Handling error is good practice to prevent the code from crashing at runtime.
But now real confusion starts from here.
What about if you do not know the python version to whom you are going to run your code? Or do you want the code to run on both Python versions?
It’s simple. Just check the version of the python and then put the if-else statement to distinguish the Python input function as per the Python version.
Suppose if you are running code on Python 2.x, it should use the raw_input() function to read user value. If the same is going to run on Python 3.x environment, it should use the input() function.
So the first task is to find the Python version number.
To get the Python version, you need to import sys module.
Use the following code snippet to read user input for both Python versions.
from sys import version_info
python_3 = version_info[0]
#creates Boolean value
#for a test that Python major version
if python_3==3:
response = input("Please enter your Good Name: ")
else:
response = raw_input("Please enter your Good Name: ")
Conclusion:
input() the function has more intelligence to interpret the user input datatype than raw_input() function.Hope you got the solution, how to Get User Input in Python for both Python 2 and Python 3 version. If you have any questions, feel free to ask me in a comment.
Happy Pythoning!
I am a Python enthusiast who loves Linux and Vim. I hold a Master of Computer Science degree from NIT Trichy and have 10 years of experience in the IT industry, focusing on the Software Development Lifecycle from Requirements Gathering, Design, Development to Deployment. I have worked at IBM, Ericsson, and NetApp, and I share my knowledge on CSEstack.org.
Hi Aniruddha
I had few doubts ..
1. The example code you given in the page
name = input(“What’s your Good name? “)
agreed it’s asking from user. let say usser provide 12345 , then
name = 12345
then when i am checking the type of name .. console should return int type.. right ?
2. what does this lines means
from sys import version_info
3. what value this version_info will return
python_3 = version_info[0]
lets assume it return 3
then python_3 is equal to 3 .. right ?
but in if condition we are not camparing the python_3 at all then how the if condition coming true ?
Thanks In Advance
Hi Madhumaya,
1) Every input you take from user using input() will be of string type, whether you pass ‘any string’ or ‘54545’.
In your case ‘name’ will be a string. You have to convert it to integer. You can do this by int(name).
2) This is the way of importing Python module/libraries. It is similar way of include header file in C/C++. In This case, we have imported version_info[] to get the Python version information. You will see “importing modules” in detail in upcoming tutorial.
3) That was a mistake in our code. I have corrected it. Thanks 🙂
Hope it is clear. Feel free to ask if you have any furher doubt.
the code to accept both the methods(for both python 2 and python 3) is showing indentation error in my system
Kindly check if you are giving a consistent number of white spaces before the start of a line in “if” and “else” block.
If you are copy-pasting the content from this tutorial. Remove those white spaces and add again manually.
If you still face an issue. Feel free to post the screenshot in out Python community – https://www.facebook.com/groups/cs.python/
How can I know which one is python 2 & python 3 versions?
Execute the following Python code
[python]from sys import version_info
python_3 = version_info[0][/python]
If the value of python_3 is 3, it is Python 3. Otherwise, Python 2.
Hi Anirudha, I am a newbie and still learning the basics of programming.
My ques is I am trying to write a simple prog that will take the input from user and compare it with some value and will reply based on that. Please check below.
[python]
age = input("enter a number: ")
if age == 17 or 18 or 19:
print("you are on right path")
elif age >= 20:
print(‘You are late but still there is always hope’)
[/python]
I want to have something like this. If the user inputted age is 17 or 18 or 19 I want to print you are on the right path and if it is more that I want to print the 2nd line. But the prob is it is always printing the 1st line.
Can you please show where I am going wrong?
Hi Asrar, two changes are required here.
1. Whenever you take user input using
input(), it always takes it as a string. You have to convert it to an integer using ‘int’.2. Change condition in first
ifstatement asage == 17 or age == 18 or age == 19:.Here is a code snippet with these two fixes.
[python]
age = int(input("enter a number: "))
if age == 17 or age == 18 or age == 19:
print("you are on right path")
elif age >= 20:
print(‘You are late but still there is always hope’)
[/python]
Reverse each word in a sentence using python with a loop statement and check its a palindrome or not.
If you are looking for the solution for your query, check these links.
Reverse string in Python.
Check if the string is a palindrome.
Hi Anirudha,
“Function input() reads the data from the user and interprets data according to the type of data entered by the user.”
^Can you clarify this further? As per taught, and as per actual coding, the ‘input( )’ function always returns string data type regardless of the input data.
Appreciate all your hard work in putting these tutorials. I’m just worried about possible confusion.
Warm regards,
SJ
Hi Solatano,
We can use the input() function with both Python versions. The input() function in Python 2 takes every input as a string. Whereas the same function in Python 3, convert the input into the appropriate data type. Edited tutorial to clear this confusion.
Thanks for bringing this topic.
print("This is not a number.)should be
print("This is not a number.")And
raw_inputwas renamed to input in Python 3.Updated. Thanks for the correction.