Question

我有一个如下文字文件。

A,B,C,D,E
A,B,C
A,B,C,E
C,D,E
C,D,E,B,A

我需要找到连续出现字符的概率。在这种情况下，B的概率发生在A

之后

B occurring after A(A->B) = (No of time B occurring after A)/(No of times A occurs)

所以概率是

3/4 = 0.75

同样明智的我需要计算所有成对概率。

A->B
B->A
A->C
C->A
A->D ...etc.

我无法弄清楚如何开始实现这个东西？使用熊猫DataFrmae也没关系。对此有何帮助？

Answer 1

蛮力：

from collections import defaultdict

data = [['A','B','C','D','E'],
        ['A','B','C'],
        ['A','B','C','E'],
        ['C','D','E'],
        ['C','D','E','B','A']]
characters = [i for j in data for i in j]
counts = {}
combinations = defaultdict(int)
for character in set(characters):
    counts[character] = characters.count(character)
    for character2 in set(characters):
        for entry in data:
            combination = [character, character2]
            if "".join(combination) in "".join(entry):
                combinations[tuple(combination)] += 1
probability = {i: combinations[i]/float(counts[i[0]]) for i in combinations}
probability

{('A', 'B'): 0.75,
  ('B', 'A'): 0.25,
  ('B', 'C'): 0.75,
  ('C', 'D'): 0.6,
  ('C', 'E'): 0.2,
  ('D', 'E'): 1.0,
  ('E', 'B'): 0.25}

连续出现字符的概率

1 个答案: