Python Projects for Beginners a ten-Week Bootcamp Approach to Python Programming

Storing User Input

In the previous cell, we simply printed out the input that the user put in. However, in order to work with the data that they enter, we need to store it into a variable:

# saving what the user inputs ans = input("What is your name? ") print("Hello { }!".format(ans) )

Go ahead and run that cell. Storing the information that the user puts in our program is as easy as storing it into a variable. This way we can work with the data they input at any point.
What Is Type Converting?
Python defines type conversion functions to directly convert one data type to another which is useful in day-to-day and competitive programming. In some situations, the data you’re working with may not be the correct type. The most obvious example is user input because no matter what the user types in, the input is taken as a string. If you are expecting a number to be input, you’ll need to convert the input to an integer data type, so that you’re able to work with it.

Checking the Type

Before we go over how to type convert, I’d like to touch on an important function that Python has which allows us to check the type of any given variable:

# how to check the data type of a variable num = 5 print( type(num) )

Go ahead and run that cell. The output here will be “”. Don’t worry about the class portion here, we’ll get into classes another week. Focus on the second part where it outputs the type as an integer. This allows us to check what data type where working with.

Converting Data Types

Python gives us the ability to type convert easily from one type to another simply by wrapping the type around the variable. Let’s check out an example of converting a string to an int:

# converting a variable from one data type to another num = "9" num = int(num) # re-declaring num to store an integer print( type(num) ) # checking type to make sure conversion worked

ChApTer 3 User InpUT And CondITIonAls
Go ahead and run that cell. We’ve just converted the string of “9” to an integer. Now we can use the variable num in any calculations. For the conversion to process correctly, we used the int() type conversion. Whatever data type is put inside of the parenthesis is converted into an int. Check Table 3-1 for how to convert from one data type to another.
Table 3-1. Converting data types