如何在python程序中使用概率

Question

我如何计算 python 中的概率？

给定具有以下值的数据集A ： [40, 10, 10, 20, 10]

如何计算收到值 10 的概率？ （10 共出现 3 次，3/5 = 0.6

这是我写的代码：

#!/usr/bin/env python3
"""reducer.py"""
import sys

# Create a dictionary to map marks
Marksprob = {}

# Get input from stdin
for line in sys.stdin:
    #Remove spaces from beginning and end of the line
    line = line.strip()

    # parse the input from mapper.py
    ClassA, Marks = line.split('\t', 1)


# Create function that returns probability percent rounded to one decimal place
def event_probability(event_outcomes, sample_space):
    probability = (event_outcomes / sample_space) * 100
    return round(probability, 1)


# Sample Space
ClassA = 25

# Determine the probability of drawing a heart
Marks = 12
grade_probability = event_probability(Marks, ClassA)

# Print each probability
print(str(grade_probability) + '%')

Answer 1

有很多方法可以做到这一点，但这里有一个可能的解决方案：

import numpy as np
import collections

npArray= np.array([40, 10, 10, 20, 10])
c=collections.Counter(npArray) # Generate a dictionary {"value":"nbOfOccurrences"}

arraySize=npArray.size
nbOfOccurrences=c[10] #assuming you want the proba to get 10

proba=(nbOfOccurrences/arraySize)*100
print(proba) #print 60.0