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NumPy: Uniform, non-uniform random sample from a given 1-D array with and without replacement

NumPy: Basic Exercise-49 with Solution

Write a NumPy program to generate a uniform, non-uniform random sample from a given 1-D array with and without replacement.

Sample Solution :

Python Code :

# Importing the NumPy library with an alias 'np'
import numpy as np 

# Printing a message indicating the generation of a uniform random sample with replacement
print("Generate a uniform random sample with replacement:") 

# Generating a random sample of 5 elements chosen from integers 0 to 6 (7 is exclusive) with replacement
print(np.random.choice(7, 5))

# Printing a message indicating the generation of a uniform random sample without replacement
print("\nGenerate a uniform random sample without replacement:") 

# Generating a random sample of 5 elements chosen from integers 0 to 6 without replacement
print(np.random.choice(7, 5, replace=False))

# Printing a message indicating the generation of a non-uniform random sample with replacement
print("\nGenerate a non-uniform random sample with replacement:") 

# Generating a random sample of 5 elements chosen from integers 0 to 6 with replacement, with custom probabilities
print(np.random.choice(7, 5, p=[0.1, 0.2, 0, 0.2, 0.4, 0, 0.1]))

# Printing a message indicating the generation of a non-uniform random sample without replacement
print("\nGenerate a uniform random sample without replacement:") 

# Generating a random sample of 5 elements chosen from integers 0 to 6 without replacement,
# with custom probabilities
print(np.random.choice(7, 5, replace=False, p=[0.1, 0.2, 0, 0.2, 0.4, 0, 0.1]))   

Sample Output:

Generate a uniform random sample with replacement:
[5 4 4 1 5]

Generate a uniform random sample without replacement:
[1 4 0 3 2]

Generate a non-uniform random sample with replacement:
[4 4 3 0 6]

Generate a uniform random sample without replacement:
[1 4 6 0 3]

Explanation:

print(np.random.choice(7, 5)): This statement generates an array of 5 random integers from the range [0, 7) (7 is not included). The random integers are chosen with replacement, which means the same integer can be chosen more than once. The results are printed.

print(np.random.choice(7, 5, replace=False)): This line generates an array of 5 random integers from the range [0, 7) without replacement. This means that each integer in the range can only be chosen once. The results are printed.

print(np.random.choice(7, 5, p=[0.1, 0.2, 0, 0.2, 0.4, 0, 0.1])): This line generates an array of 5 random integers from the range [0, 7) with replacement and with custom probabilities for each integer. The probabilities are provided in the p parameter as a list [0.1, 0.2, 0, 0.2, 0.4, 0, 0.1]. The sum of all probabilities in the list should be equal to 1. The results are printed.

print(np.random.choice(7, 5, replace=False, p=[0.1, 0.2, 0, 0.2, 0.4, 0, 0.1])): This line generates an array of 5 random integers from the range [0, 7) without replacement and with custom probabilities for each integer, as specified in the p parameter. The results are printed.

Python-Numpy Code Editor:

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