.choices()

The .choices() function in Python returns a list of randomly selected elements from a given sequence, allowing weighted probabilities and repetition.

Syntax

random.choices(sequence, weights=None, *, cum_weights=None, k=1)

• sequence : The sequence (list, tuple, etc.) from which random elements are chosen.
• weights (Optional): A sequence of relative weights corresponding to each element in sequence, determining the likelihood of selection.
• cum_weights (Optional): A sequence of cumulative weights. It is an alternative to weights and cannot be used simultaneously.
• k (Optional): The number of elements to select. Defaults to 1.

Note: Either weights or cum_weights can be used, but not both.

Example 1

The following example uses .choices() to randomly select 10 fruits from a predefined list, where the likelihood of each fruit being chosen is determined by its respective weights:

import random

# Define the population of items
fruits = ['apple', 'banana', 'cherry', 'date']

# Define weights for each fruit (higher weight means higher likelihood of selection)
weights = [5, 20, 50, 25]  # 'cherry' is most likely to be picked, followed by 'date', 'banana', and 'apple'

# Number of random selections to make
num_picks = 10

# Randomly select items based on the weights
selected_fruits = random.choices(fruits, weights=weights, k=num_picks)

# Output the selected items
print("Randomly selected fruits:", selected_fruits)

The above code produces the following output:

Randomly selected fruits: ['cherry', 'date', 'apple', 'cherry', 'cherry', 'cherry', 'cherry', 'cherry', 'date', 'date']

The output changes with each execution as random.choices() generates random selections influenced by the weights.

Codebyte Example

This example uses .choices() to randomly draw 5 cards from a deck, assigning higher weights to face cards to make them more likely to be selected:

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