Python | random.sample() function

Last Updated : 29 Aug, 2018

sample() is an inbuilt function of random module in Python that returns a particular length list of items chosen from the sequence i.e. list, tuple, string or set. Used for random sampling without replacement.

Syntax : random.sample(sequence, k)

Parameters:
sequence: Can be a list, tuple, string, or set.
k: An Integer value, it specify the length of a sample.

Returns: k length new list of elements chosen from the sequence.

Code #1: Simple implementation of sample() function.

# Python3 program to demonstrate 
# the use of sample() function . 
  
# import random  
from random import sample 
  
# Prints list of random items of given length 
list1 = [1, 2, 3, 4, 5]  
  
print(sample(list1,3)) 

Output:

[2, 3, 5]

Code #2: Basic use of sample() function.

# Python3 program to demonstrate 
# the use of sample() function . 
  
# import random  
import random 
  
  
# Prints list of random items of 
# length 3 from the given list. 
list1 = [1, 2, 3, 4, 5, 6]  
print("With list:", random.sample(list1, 3)) 
  
# Prints list of random items of 
# length 4 from the given string.  
string = "GeeksforGeeks"
print("With string:", random.sample(string, 4)) 
  
# Prints list of random items of 
# length 4 from the given tuple. 
tuple1 = ("ankit", "geeks", "computer", "science", 
                   "portal", "scientist", "btech") 
print("With tuple:", random.sample(tuple1, 4)) 
  
  
# Prints list of random items of 
# length 3 from the given set. 
set1 = {"a", "b", "c", "d", "e"} 
print("With set:", random.sample(set1, 3)) 

Output:

With list: [3, 1, 2]
With string: ['e', 'f', 'G', 'G']
With tuple: ['ankit', 'portal', 'geeks', 'computer']
With set: ['b', 'd', 'c']

Note: Output will be different everytime as it returns a random item.

Code #3: Raise Exception

If the sample size i.e. k is larger than the sequence size, ValueError is raised.

# Python3 program to demonstrate the 
# error of sample() function. 
import random 
  
list1 = [1, 2, 3, 4]  
   
# exception raised 
print(random.sample(list1, 5))  

Output:

Traceback (most recent call last):
  File "C:/Users/user/AppData/Local/Programs/Python/Python36/all_prgm/geeks_article/sample_method_article.py", line 8, in 
    print(random.sample(list1, 5))
  File "C:\Users\user\AppData\Local\Programs\Python\Python36\lib\random.py", line 317, in sample
    raise ValueError("Sample larger than population or is negative")
ValueError: Sample larger than population or is negative

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