Numbers/Integers in Python

Python as a calculator

----------------------

Interpreter can act as a calculator. Numbers such as 2, 4, and 30 have type `int` while 5.0 and 1.6 are of type `float`	>>> 2 + 2 4 >>> 50 - 5*6 20 >>> (50 - 5*6) / 4 5.0 >>> 8 / 5  # division always returns a floating point number 1.6
Division using `/` always returns a float. To discard fractional part, use `//` (floor division). Calculating the remainder is done via `%` (modulus operator).	>>> 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
Calculating powers is also possible.	>>> 5 ** 2  # 5 squared 25 >>> 2 ** 7  # 2 to the power of 7 128
`=` sign is used to assign value to a variable	>>> width = 20 >>> height = 5 * 9 >>> width * height 900
If a variable is not "defined" (assigned a value), trying to use it will give you an error	>>> n  # try to access an undefined variable Traceback (most recent call last):   File "", line 1, in NameError: name 'n' is not defined
Python always tries to display result as a floating number	>>> 3 * 3.75 / 1.5  # int * float / float 7.5                 # results to a float >>> 7.0 / 2  # float / int 3.5          # results to a float
You may do a continuous calculation because the last printed expression is assigned to `_` NOTE: don't assign a value to `_`	>>> tax = 12.5 / 100 >>> price = 100.50 >>> price * tax 12.5625             # this is assigned to `_` >>> price + _       # you can access the last value by calling `_` 113.0625 >>> round(_, 2) 113.06
Other number types supported	1. decimal 2. fraction 3. complex numbers e.g: >>> 3 + 5j - 5 - 5j (-2+0j) >>>

Operations on numbers

---------------------

Ways of limiting decimal places	>>> import math >>> pi = math.pi >>> pi 3.141592653589793 >>> >>> print('{0:.2f}'.format(pi)) 3.14 >>> print('%.2f' % pi) 3.14 >>> print(round(pi,2)) 3.14 >>>
Rounding numbers	>>> round(123.454665575777) 123 >>> round(123.454665575777, 5) 123.45467 >>>
Extracts decimal part	>>> x 2.34 >>> int(str(x).partition('.')[2]) 34 >>>
Converts int to binary and vice versa	>>> bin(23) '0b10111' >>> int('10111', 2) 23 >>>