Numbers in Python

Python as a calculator 
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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 "<stdin>", line 1, in <module>  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 

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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  >>>