替换Python中的缺失值 [英] Substituting missing values in Python

问题描述

我想用最后一个先前的已知值替换缺失值(无).这是我的代码.但这是行不通的.有什么更好的算法建议吗?

I want to substitute missing values (None) with the last previous known value. This is my code. But it doesn't work. Any suggestions for a better algorithm?

t = [[1, 3, None, 5, None], [2, None, None, 3, 1], [4, None, 2, 1, None]]
def treat_missing_values(table):
    for line in table:
        for value in line:
            if value == None:
                value = line[line.index(value)-1]
    return table

print treat_missing_values(t)

推荐答案

这可能是我要这样做的方式:

This is probably how I'd do it:

>>> def treat_missing_values(table):
...     for line in table:
...         prev = None
...         for i, value in enumerate(line):
...             if value is None:
...                 line[i] = prev
...             else:
...                 prev = value
...     return table
... 
>>> treat_missing_values([[1, 3, None, 5, None], [2, None, None, 3, 1], [4, None, 2, 1, None]])
[[1, 3, 3, 5, 5], [2, 2, 2, 3, 1], [4, 4, 2, 1, 1]]
>>> treat_missing_values([[None, 3, None, 5, None], [2, None, None, 3, 1], [4, None, 2, 1, None]])
[[None, 3, 3, 5, 5], [2, 2, 2, 3, 1], [4, 4, 2, 1, 1]]

这篇关于替换Python中的缺失值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！