Examples of random.seed( ) in Python

random.seed() function can help save the state of random functions. Thus, by using seed(), these random functions can generate the same numbers on multiple code executions.

Example 1

Example 1 shows how to use random.seed() and how it impacts the generated numbers.

Note that, random.random() generates a floating point number in the range 0.0 <= X < 1.0.

# importing random module
import random 

# set seed - time 1
random.seed(235)
# generate a floating point number - time 1
Generated_number_1 = random.random() 
print("Floating Number - time 1 - with seed(235): \n", Generated_number_1 )

# set seed - time 2
random.seed(235)
# generate a floating point number - time 2
Generated_number_2 = random.random() 
print("Floating Number - time 2 - with seed(235): \n", Generated_number_2 )

The following is the output. It shows that they generate the same random number because there is a random.seed(235).

Floating Number - time 1 - with seed(235): 
 0.34681819919543666

Floating Number - time 2 - with seed(235): 
 0.34681819919543666

Example 2

Example 2 adds time 3, which does not have a random.seed(). Thus, by comparing these 3 times, we can see the difference between with random.seed() and without random.seed().

Note that, random.randint() generates integer numbers in the range you specify.

# importing random module
import random

# set seed - time 1
random.seed(123)
# generate an integer - time 1
Generated_number_1 = random.randint(2, 90) 
print("Integer Number - time 1 - with seed(123): \n", Generated_number_1 )

# set the same seed - time 2
random.seed(123)
# generate an integer - time 2
Generated_number_2 = random.randint(2, 90) 
print("Integer Number - time 2 - with seed(123): \n", Generated_number_2 )

# generate an integer - time 3 - no seed
Generated_number_3 = random.randint(2, 90) 
print("Integer Number - time 3 - no seed: \n", Generated_number_3 )

The following is the output, which shows the differences between 3 different times.

It is worth noting that random.seed() does not set seed for time 3, even though random.randint() is in the same Python code block as times 1 and 2.

Integer Number - time 1 - with seed(123): 
 8

Integer Number - time 2 - with seed(123): 
 8

Integer Number - time 3 - no seed: 
 36

Example 1

Example 2

Further Reading