Number data types store numeric values. Number objects are created when you assign a value to them. For example a = 1, b = 20. You can also delete the reference to a number object by using the del statement. The syntax of the del statement is as follows.

del variable1[,variable2[,variable3[...,variableN]]]]

You can delete a single object or multiple objects by using the del statement. For example

del a
del a,b

Python supports four different numerical types.

• int (signed integers)
• long (long integers, they can also be represented in octal and hexadecimal)
• float (floating point real values)
• complex (complex numbers)

Integers can be of any length, it is only limited by the memory available. A floating point number is accurate up to 15 decimal places. Integer and floating points are separated by decimal points. 1 is integer, 1.0 is floating point number. Complex numbers are written in the form, x + yj, where x is the real part and y is the imaginary part.

Example Program

a,b,c,d=1,1.5,231456987,2+9j

print("a=",a)
print("b=",b)
print("c=",c)
print("d=",d)

Output

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Python provides various built-in mathematical functions to perform mathematical calculations. The following Table 2.1 provides various mathematical functions and its purpose. For using the below functions, all functions except abs(x), max(x1,x2,..., xn), min(x1,x2,..., xn), round(x[n]) and pow(x,y) need to import the math module because these functions reside in the math module. The math module also defines two mathematical constants pi and e. Modules will be discussed in Chapter 5.

Table 2.1 Mathematical Functions

Example Program

import math

print("Absolute value of - 120:", abs(- 120))
print("Square root of 25:", math.sqrt(25))
print("Ceiling of 12.2:", math.ceil(12.2))
print("Floor of 12.2:", math.floor(12.2))
print("2 raised to 3:", pow(2,3))
print("Exponential of 3:", math.exp(3))
print("Absolute value of - 123:", math.fabs(- 123))
print("Natural Logarithm of 2:", math.log(2))
print("Logarithm to the Base 10 of 2:", math.log10(2))
print("Largest among 10, 4, 2:", max(10, 4, 2))
print("Smallest among 10, 4, 2:", min(10, 4, 2))
print("12.6789 rounded to 2 decimal places:", round(12.6789, 2))
print("Decimal part and integer part of 12.090876:", math.modf(12.090876))

Output

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There are several built-in trigonometric functions in Python. The function names and its purpose are listed in Table 2.2.

Table 2.2 Trigonometric Functions

Example

import math

print("Sin(90):",math.sin(90))
print("Cos(90):",math.cos(90))
print("Tan(90):",math.tan(90))
print("asin(1):",math.asin(1))
print("acos(1):",math.acos(1))
print("atan(1):",math.atan(1))
print("atan2(3,2):",math.atan2(3,2))
print("Hypotenuse of 3 and 4: ",math.hypot(3,4))
print("Degrees of 90: ",math.degrees(90))
print("Radians of 90: ",math.radians(90))

Output

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There are several random number functions supported by Python. Random numbers have applications in research, games, cryptography, simulation and other applications. Table 2.3 shows the commonly used random number functions in Python. For using the random number functions, we need to import the module random because all these functions reside in the random module.

Table 2.3 Random Number Functions

Example

import random
s = 'abcde'
print("choice(abcde):", random.choice(s))
list = [10,2,3,1,8,19]
print("shuffle(list):", random.shuffle(list))
print("random.seed(20):", random.seed(20))
print("random():", random.random())
print("uniform(2,3):", random.uniform(2,3))
print("randrange(2,10,1):", random.randrange(2,10,1))

Output

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