Python | SymPy Permutation.descents() method

Permutation.descents() : descents() is a sympy Python library function that returns the position of descents in the permutation. Descents are the elements where a[i] > a[i+1]

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

Return : position of descents in the permutation

Code #1 : descents() Example

# Python code explaining
# SymPy.descents()

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

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

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

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


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

Output :

Permutation a – descents form : [1]
Permutation b – descents form : [2, 3, 4]

Code #2 : descents() Example – 2D Permutation

# Python code explaining
# SymPy.descents()

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

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

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


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

Output :

Permutation a – descents form : [0, 3, 5]