SymPy | Permutation.unrank_lex() in Python

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Permutation.unrank_lex() : unrank_lex() is a sympy Python library function that returns the Lexicographic permutation unranking.

Syntax : sympy.combinatorics.permutations.Permutation.unrank_lex()

Return : Lexicographic permutation unranking

Code #1 : unrank_lex() Example

# Python code explaining 
# SymPy.Permutation.unrank_lex() 
  
# importing SymPy libraries 
from sympy.combinatorics.partitions import Partition 
from sympy.combinatorics.permutations import Permutation 
  
# Using from sympy.combinatorics.permutations.Permutation.unrank_lex() method  
  
# creating Permutation 
a = Permutation([[2, 0], [3, 1]]) 
  
b = Permutation([1, 3, 5, 4, 2, 0]) 
  
size = 2
rank = 5
  
print ("Permutation a - unrank_lex form : ", a.unrank_lex(size, rank)) 
print ("Permutation b - unrank_lex form : ", b.unrank_lex(size, 2)) 

Output :

Permutation a – unrank_lex form : (0 1)
Permutation b – unrank_lex form : (1)

Code #2 : unrank_lex() Example

# Python code explaining 
# SymPy.Permutation.unrank_lex() 
  
# importing SymPy libraries 
from sympy.combinatorics.partitions import Partition 
from sympy.combinatorics.permutations import Permutation 
  
# Using from  
# sympy.combinatorics.permutations.Permutation.unrank_lex() method  
  
# creating Permutation 
a = Permutation([[2, 4, 0],  
                 [3, 1, 2], 
                 [1, 5, 6]]) 
  
  
print ("Permutation a - unrank_lex form : ", a.unrank_lex(5, 2)) 