Python: Generate the combinations of n distinct objects taken from a list
Python List: Exercise - 82 with Solution
Write a Python program to generate the combinations of n distinct objects taken from the elements of a given list.
Sample Solution:
Python Code:
def combination(n, n_list):
if n<=0:
yield []
return
for i in range(len(n_list)):
c_num = n_list[i:i+1]
for a_num in combination(n-1, n_list[i+1:]):
yield c_num + a_num
n_list = [1,2,3,4,5,6,7,8,9]
print("Original list:")
print(n_list)
n = 2
result = combination(n, n_list)
print("\nCombinations of",n,"distinct objects:")
for e in result:
print(e)
Sample Output:
Original list: [1, 2, 3, 4, 5, 6, 7, 8, 9] Combinations of 2 distinct objects: [1, 2] [1, 3] [1, 4] [1, 5] [1, 6] [1, 7] [1, 8] [1, 9] [2, 3] [2, 4] [2, 5] [2, 6] [2, 7] [2, 8] [2, 9] [3, 4] [3, 5] [3, 6] [3, 7] [3, 8] [3, 9] [4, 5] [4, 6] [4, 7] [4, 8] [4, 9] [5, 6] [5, 7] [5, 8] [5, 9] [6, 7] [6, 8] [6, 9] [7, 8] [7, 9] [8, 9]
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Previous: Write a Python program to extract a given number of randomly selected elements from a given list.
Next: Write a Python program to round every number of a given list of numbers and print the total sum multiplied by the length of the list.
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Python: Tips of the Day
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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