Udit Vashisht
Author: Udit Vashisht


Chapter 7- Numbers, Conversions and Operators

Chapter 7- Numbers, Conversions and Operators

  • March 11, 2019, 12:11 p.m.
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Chapter 7- Numbers, Conversions and Operators

In the previous chapter, we learned about various data types. From this chapter onward, we will learn in detail about each data type.

Numbers

This data type stores the numeric values and is immutable. For the beginners, it is sufficient to understand that immutable objects are those which can not be changed once created (Though this subject needs a deeper and detailed post). It can be further divided into three types:-

  1. int - Often called integers, these are positive or negative whole numbers with no decimal point. Prior to Python 3, Python 2 had int and long int types but the long int has been discontinued in Python 3 and now the int can be of unlimited size. e.g. 1, 2, -3, 99 etc.
  2. float - They have decimal point separating the integer from the fraction e.g. 22.0 , 5.0, -22.0 etc.
  3. complex - They are of the form a + bj. ‘a’ is the real part, ‘b’ is the imaginary part and j is the square root of -1. Also, both ‘a’ and ‘b’ are floats.

Python has a built-in function type() which tells you the data-type.

>>> type(2)
<class 'int'>
>>> type(2.0)
<class 'float'>
>>> type(3+4j)
<class 'complex'>

Conversions

In Python, one type of number can be easily converted into another type and it is called ‘coercion’

Any mathematical operation will coerce an integer to a float if one of the operands is a float. Also, the result of the division (/) will always be a float irrespective of whether the operands were integers or floats.

>>> 1 + 2.0
3.0
>>> 1*5.0
5.0
>>> 5/1
5.0
>>> a = 10
>>> b = 2
>>> c = a/b
>>> type(a)
<class 'int'>
>>> type(b)
<class 'int'>
>>> type(c)
<class 'float'>
>>> 

Alternatively, you can convert the numbers as under:-

  1. int(x) will convert x to a plain integer. Also, it will convert the float into the lower integer. i.e int (2.9) will give 2.
  2. float(x) will convert x to a floating-point number.
  3. complex(x) will convert x to a complex number with imaginary part ‘0’.
  4. complex(x,y) will result into x + yj.
>>> int(1.0)
1
>>> int (2.9)
2
>>> float (25)
25.0
>>> complex(2)
(2+0j)
>>> complex(2,3)
(2+3j)

Operators
Before getting into operators, we must note that in all the below mentioned operators except the division (/) operator, the result will be float only if one or both of the operands are floats. If both of them are integers, then the result will be an integer.

  1. Addition (+) - e.g. 2 + 1 = 3.
  2. Subtraction(-)- e.g. 3 - 1 = 2.
  3. Multiplication(*) - e.g. 5 * 2 = 10.
  4. Division(/) - e.g. 4/2. In this case the result will be a float i.e. 2.0 even when both the operands were integers.
  5. Truncation/Floor Division(//). It will truncate the fractional part if any and result will be an integer. e.g. 5//2 = 2. In mathematical terms, it will give you the quotient.
  6. Modulo (%)- It will give the remainder as an answer. e.g. 5 % 3 = 2.
  7. Exponentiation - e.g. 5 ** 2 = 25.
>>> 2 + 1
3
>>> 2.0 + 1
3.0
>>> 3 - 1
2
>>> 3 - 1.0
2.0
>>> 5 * 2 
10
>>> 5.0 * 2
10.0
>>> 4/2
2.0
>>> 5//2
2
>>> 5//2.0
2.0
>>> 5%3
2
>>> 5.0%3
2.0
>>> 5**2
25

Table of Contents

Chapter 6 - Data Types & Variables



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