Python SymPy Permutation.index()方法

Permutation.index() : index()是一个sympy Python库函数，返回参数中permutation的索引值。

一个包络的指数=所有子符号j的总和，使包络[j]大于包络[j+1]。

语法 : sympy.combinatorics.permutations.Permutation.index()

返回 :
变化的索引值

代码 #1 : index() 示例

# 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())

输出 :

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

代码#2：index()实例–二维排列组合

# 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())