Numbers

Number data type stores numeric values. They are immutable data types i.e changing the value of a number data type results in a newly allocated object.

Number objects are created when you assign a value to them. For example

val1 = 1
val2 = 15

To delete a reference to a number object, you use the del statement as follows:

del val1

Python supports the following numerical types:

Int (signed integer) – they are positive or negative whole numbers without a decimal point.

Float – these represent real numbers with decimal points eg 109.50

Complex numbers –  these use the j or J suffix to indicate the imaginary part (e.g. 3+5j).

Number Type Conversion

We use type conversion to convert one type to another in order to satisfy  certain requirements of an operator or a function

Type int(num) to convert a number to a plain integer

Type float(num) to convert a number to a decimal or floating-point number

Type complex(num) to convert a num to a complex number with real part num and an imaginary part 0

Mathematical Function

 Python supports various Maths functions. Here are some of the common functions:

max(num1, num2)  – finds the largest of given arguments

min(num1, num2) – finds the smallest of the given  arguments

pow(num, exp) – returns the power of a number i.e result of num**exp

sqrt(num) – returns the square-root of a number 

You can check out more maths functions supported by Python in the official documentation.

Random Number Function

Python defines a set of functions that are used to generate or manipulate random numbers. This particular type of functions are used in a lot of games, lotteries or any application requiring random number generation.

The following are some of the random functions:

choice(seq) – returns a random number from a list, tuple or strings

randomrange([start,], stop, [,step]) A randomly selected element from range(start, stop, step).

random()  – This number is used to generate a float random number less than 1 and greater or equal to 0.

seed() – Sets the integer starting value used in generating random numbers. Call this function before calling any other random module function. Returns None.

shuffle(lst) – Randomizes the items of a list in place. Returns None.

uniform(a,b) This function is used to generate a floating-point random number between the numbers mentioned in its arguments. It takes two arguments, lower limit(included in generation) and upper limit(not included in generation).

Example to illutstrate random number functions

python"># Python code to demonstrate the working of random functions and maths functions

# importing "random" for random operations
import random

# Initializing list 
li = [1, 4, 5, 10, 2]

# Examples of math functions, max, min, pow
print min(2,4,5,8)

print max(4,2,5,1)

print pow(2,2)

# Printing list before shuffling
print ("The list before shuffling is : ")
print li

# using shuffle() to shuffle the list
random.shuffle(li)

# Printing list after shuffling
print ("The list after shuffling is : ")
print li

# using uniform() to generate random floating number in range
# prints number between 5 and 10
print ("The random floating point number between 5 and 10 is : ")
print (random.uniform(5,10))

# using random() to generate a random number 
# between 0 and 1 
print ("A random number between 0 and 1 is : ") 
print (random.random())

# using seed() to seed a random number 
random.seed(5) 

# printing mapped random number 
print ("The mapped random number with 5 is : ") 
print (random.random())


# using choice() to generate a random number from a given list of numbers. 
print ("A random number from list is : ") 
print (random.choice([1, 4, 8, 10, 3])) 

# using randrange() to generate in range from 20 to 50. The last parameter 3 is step size to skip 
# three numbers when selecting. 
print ("A random number from range is : ") 
print (random.randrange(20, 50, 3))


The output of the above when executed will be as follows. Note the result will be different each time you run it.

The list before shuffling is : 
[1, 4, 5, 10, 2]
The list after shuffling is : 
[5, 1, 4, 10, 2]
The random floating point number between 5 and 10 is : 
6.47318352507
A random number between 0 and 1 is : 
0.630486433207
The mapped random number with 5 is : 
0.62290169489
A random number from list is : 
10
A random number from range is : 
41