# random.lognormvariate() function in Python

Last Updated : 26 May, 2020

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 :

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