User Input

Interactive input

To get input from the user, use the input function (note: in Python 2.x, the function is called raw_input instead, although Python 2.x has its own version of input that is completely different):

@Ver ≥ 2.3

name = raw_input("What is your name? ")
# Out: What is your name? _

Security Remark Do not use input() in Python2 - the entered text will be evaluated as if it were a Python expression (equivalent to eval(input()) in Python3), which might easily become a vulnerability. See this article for further information on the risks of using this function.

@Ver end

@Ver ≥ 3.0

name = input("What is your name? ")
# Out: What is your name? _

@Ver end

The remainder of this example will be using Python 3 syntax.

The function takes a string argument, which displays it as a prompt and returns a string. The above code provides a prompt, waiting for the user to input.

name = input("What is your name? ")
# Out: What is your name?

If the user types “Bob” and hits enter, the variable name will be assigned to the string "Bob":

name = input("What is your name? ")
# Out: What is your name? Bob
print(name)
# Out: Bob

Note that the input is always of type str, which is important if you want the user to enter numbers. Therefore, you need to convert the str before trying to use it as a number:

x = input("Write a number:")
# Out: Write a number: 10
x / 2
# Out: TypeError: unsupported operand type(s) for /: 'str' and 'int'
float(x) / 2
# Out: 5.0

NB: It’s recommended to use try/except blocks to catch exceptions when dealing with user inputs. For instance, if your code wants to cast a raw_input into an int, and what the user writes is uncastable, it raises a ValueError.