Python | SymPy Permutation.index() method

Python | SymPy Permutation.index() method

Last Updated : 27 Aug, 2019

Permutation.index() : index() is a sympy Python library function that returns the index value of the permutation in argument. Index of a permutation = Sum of all subscripts j such that permutation[j] is greater than permutation[j+1].

Syntax : sympy.combinatorics.permutations.Permutation.index() Return : index value of the permutation

Code #1 : index() Example

Python3 1=1

# Python code explaining
# SymPy.Permutation.index()

# importing SymPy libraries
from sympy.combinatorics.partitions import Partition
from sympy.combinatorics.permutations import Permutation

# Using from sympy.combinatorics.permutations.Permutation.index() method 

# creating Permutation
a = Permutation([[2, 0], [3, 1]])

b = Permutation([1, 3, 5, 4, 2, 0])


print ("Permutation a - index form : ", a.index())
print ("Permutation b - index form : ", b.index())

Output :

Permutation a - index form : 1 Permutation b - index form : 9

Code #2 : index() Example - 2D Permutation

Python3 1=1

# Python code explaining
# SymPy.Permutation.index()

# importing SymPy libraries
from sympy.combinatorics.partitions import Partition
from sympy.combinatorics.permutations import Permutation

# Using from sympy.combinatorics.permutations.Permutation.index() method 

# creating Permutation
a = Permutation([[2, 4, 0], 
                 [3, 1, 2],
                 [1, 5, 6]])


print ("Permutation a - index form : ", a.index())

Output :

Permutation a - index form : 8

Python | SymPy Permutation.index() method

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