Permutación y Combinación en Python

Python proporciona métodos directos para encontrar permutaciones y combinaciones de una secuencia. Estos métodos están presentes en el paquete itertools.

Permutación 

Primero importe el paquete itertools para implementar el método de permutaciones en python. Este método toma una lista como entrada y devuelve una lista de objetos de tuplas que contienen todas las permutaciones en forma de lista. 
 

# A Python program to print all 
# permutations using library function 
from itertools import permutations 
  
  
# Get all permutations of [1, 2, 3] 
perm = permutations([1, 2, 3]) 
  
# Print the obtained permutations 
for i in list(perm): 
    print (i) 

# A Python program to print all 
# permutations of given length 
from itertools import permutations 
  
# Get all permutations of length 2 
# and length 2 
perm = permutations([1, 2, 3], 2) 
  
# Print the obtained permutations 
for i in list(perm): 
    print (i) 

# A Python program to print all 
# combinations of given length
from itertools import combinations
  
# Get all combinations of [1, 2, 3]
# and length 2
comb = combinations([1, 2, 3], 2)
  
# Print the obtained combinations
for i in list(comb):
    print (i)

# A Python program to print all 
# combinations of a given length 
from itertools import combinations 
  
# Get all combinations of [1, 2, 3] 
# and length 2 
comb = combinations([1, 2, 3], 2) 
  
# Print the obtained combinations 
for i in list(comb): 
    print (i)

# A Python program to print all combinations 
# of given length with unsorted input. 
from itertools import combinations 
  
# Get all combinations of [2, 1, 3] 
# and length 2 
comb = combinations([2, 1, 3], 2) 
  
# Print the obtained combinations 
for i in list(comb): 
    print (i)

# A Python program to print all combinations 
# with an element-to-itself combination is 
# also included 
from itertools import combinations_with_replacement 
  
# Get all combinations of [1, 2, 3] and length 2 
comb = combinations_with_replacement([1, 2, 3], 2) 
  
# Print the obtained combinations 
for i in list(comb): 
    print (i)