对于一个经验丰富的Python编程人员来说，实现一个Python算法其实并不困难。我们今天就为大家介绍了这样的操作方法，大家可以以此为学习参考对象，在实践中去总结经验技巧，来熟练掌握这一技术。
Python算法具体操作代码示例：
- # -*- coding: UTF8 -*-
- import sys
- import copy
- def init_pass(T):
- C = {}
- for t in T:
- for i in t:
- if i in C.keys():
- C[i] += 1
- else:
- C[i] = 1
- return C
- def candidate_gen(F):
- C = []
- k = len(F[0]) + 1
- for f1 in F:
- for f2 in F:
- if f1[k-2] < f2[k-2]:
- c = copy.copy(f1)
- c.append(f2[k-2])
- flag = True
- for i in range(0,k-1):
- s = copy.copy(c)
- s.pop(i)
- if s not in F:
- flag = False
- break
- if flag and c not in C:
- C.append(c)
- return C
- def compare_list(A,B):
- if len(A) <= len(B):
- for a in A:
- if a not in B:
- return False
- else:
- for b in B:
- if b not in A:
- return False
- return True
- def apriori(T, minsup):
- C = []
- init = init_pass(T)
- keys = init.keys()
- keys.sort()
- C.append(keys)
- n = len(T)
- F = [[]]
- for f in C[0]:
- if init[f]*1.0/n >= minsup:
- F[0].append([f])
- k = 1
- while F[k-1] != []:
- C.append(candidate_gen(F[k-1]))
- F.append([])
- for c in C[k]:
- count = 0;
- for t in T:
- if compare_list(c,t):
- count += 1
- if count*1.0/n >= minsup:
- F[k].append(c)
- k += 1
- U = []
- for f in F:
- for x in f:
- U.append(x)
- return U
- T = [['A','B','C','D'],['B','C','E'],['A','B','C','E'],
['B','D','E'],['A','B','C','D']]- F = apriori(T, 0.9)
- print F
Python算法相关代码编写方法就为大家介绍到这里。
【编辑推荐】
