Python

float. We will see more about numeric types later in the tutorial.

     # this is the first comment

spam = 1 # and this is the second comment

# ... and now a third!

text = "# This is not a comment because it's inside quotes."

     >>> 2 + 2

4

>>> 50 - 5*6 20

>>> (50 - 5*6) / 4

5.0

>>> 8 / 5 # division always returns a floating point number 1.6

  9

Python Tutorial, Release 3.7.0

 Division (/) always returns a float. To do floor division and get an integer result (discarding any fractional result) you can use the // operator; to calculate the remainder you can use %:

    >>> 17 / 3 # classic division returns a float 5.666666666666667

>>>

>>> 17 // 3 # floor division discards the fractional part 5

>>> 17 % 3 # the % operator returns the remainder of the division 2

>>> 5 * 3 + 2 # result * divisor + remainder

17

 With Python, it is possible to use the ** operator to calculate powers1:

The equal sign (=) is used to assign a value to a variable. Afterwards, no result is displayed before the next interactive prompt:

If a variable is not “defined” (assigned a value), trying to use it will give you an error:

There is full support for floating point; operators with mixed type operands convert the integer operand to floating point:

In interactive mode, the last printed expression is assigned to the variable _. This means that when you are using Python as a desk calculator, it is somewhat easier to continue calculations, for example:

This variable should be treated as read-only by the user. Don’t explicitly assign a value to it — you would create an independent local variable with the same name masking the built-in variable with its magic behavior.

1 Since ** has higher precedence than -, -3**2 will be interpreted as -(3**2) and thus result in -9. To avoid this and get