Python random sample














































Python random sample



Python random  : sample() 

 

In this article, we will learn how to use the random.sample() function to choose multiple items from a list, set, and dictionary. Python's random module provides random.sample() function for random sampling and randomly pick more than one element from the list without repeating elements. The random.sample() returns a list of unique elements chosen randomly from the list, sequence, or set, we call it random sampling without replacement.


Syntax :

random.sample(sequence, k)

Parameter Values

ParameterDescription
sequenceRequired. A sequence. Can be any sequence: list, set, range etc.
kRequired. The size of the returned list
 

Return Value :

k length new list of elements chosen from the sequence.

- A random.sample() function raises a type error if you miss any of the required arguments.


EXAMPLES :

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 : 

[5, 4, 2]





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 = "Cppsecrets"
print("With string:", random.sample(string, 4)) 

# Prints list of random items of 
# length 4 from the given tuple. 
tuple1 = ("vishal", "cpp", "computer", "science", 
                "portal", "secrets", "btech") 
print("With tuple:", random.sample(tuple1, 4)) 


# Prints list of random items of 
# length 3 from the given set. 
set1 = {"c", "p", "p", "s", "e", "c", "r", "e", "t", "s"} 
print("With set:", random.sample(set1, 3)) 

Output: 

With list: [8, 10, 6]                                                                                                                          
With string: ['c', 'r', 't', 't']                                                                                                             
With tuple: ['portal', 'vishal', 'science', 'secrets']                                                                                           
With set: ['r', 't', 'c']





Note: As you can see the random.sample() function doesn't repeat the items in the result list. This is also called a random sample without replacement. If you want to generate random samples without replacement out of a list or population then you should use random.sample().

Points to remember about Python random.sample()

  • It is used for random sampling without replacement.
  • It doesn't change the specified sequence or list. It returns a new sampled list containing elements from the specified sequence or list.
  • The specified list or population need not be hashable or unique.

Important Note:

If your list itself contains repeated or duplicate elements, then random.sample() can pick repeated items because each occurrence is a possible selection in the sample. I.e., The random.sample() can pick the repeated items from the specified list if the unique members are less than a sampling size.


random.sample() function Error and exception

A sample function can raise the following two errors.

  • ValueError If the sample size is larger than the population (i.e., list or set) size
  • TypeError if any of the two arguments is missing.
Here is the example


Output: 


     

*******END OF ARTICLE*******


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