random.lognormvariate() function in Python

random module is used to generate random numbers in Python. Not actually random, rather this is used to generate pseudo-random numbers. That implies that these randomly generated numbers can be determined.

random.lognormvariate()

lognormvariate() is an inbuilt method of the random module. It is used to return a random floating point number with log-normal distribution.

Syntax : random.lognormvariate(mu, sigma)

Parameters :
mu : mean
sigma : standard deviation, greater than 0

Returns : a random log-normal distribution floating number

Example 1:

# import the random module
import random

# determining the values of the parameters
mu = 0
sigma = 0.25

# using the lognormvariate() method
print(random.lognormvariate(mu, sigma))

Output :

0.8585439051088984

Example 2: We can generate the number multiple times and plot a graph to observe the log-normal distribution.

# import the required libraries
import random
import matplotlib.pyplot as plt

# store the random numbers in a
# list
nums = []
mu = 0
sigma = 0.25

for i in range(100):
    temp = random.lognormvariate(mu, sigma)
    nums.append(temp)

# plotting a graph
plt.plot(nums)
plt.show()

Output :

Example 3: We can create a histogram to observe the density of the log-normal distribution.

# import the required libraries
import random
import matplotlib.pyplot as plt

# store the random numbers in a list
nums = []
mu = 0
sigma = 0.25

for i in range(10000):
    temp = random.lognormvariate(mu, sigma)
    nums.append(temp)

# plotting a graph
plt.hist(nums, bins = 200)
plt.show()

Output :