根据索引的日期时间过滤器设置列值 [英] Set column value based on indexed datetime filter

问题描述

我想基于python，pandas中的白天过滤器(DateTime值在索引列中)填充列的值.

I would like to fill the values of a column based on a daytime filter (the DateTime values are in the index column) in python, pandas.

我面临的问题是我的日期时间已经设置为索引，因此，解决这个问题的旧方法"行不通.

The problem I am facing is that my datetimes are already set as index, therefore, the "old way" I was solving this problem does not work.

到目前为止，对于类似的问题，我正在使用这种方法:

So far for similar problems I was using this approach:

df.loc[df['filter'] > 0, 'column_value'] = 1

但是，现在过滤器"列实际上是索引，我在两个日期之间对其进行过滤，因此首先没有布尔值.

However now the 'filter' column is actually the index and I filter it between two dates, so there is no boolean in the first place.

所以我尝试了:

df[df['2017.01.19  12:30:00':'2017.01.19  15:10:00'], "column_value"] = "something"

但是我收到TypeError: 'DataFrame' objects are mutable, thus they cannot be hashed类型错误.

如果我尝试:df[df['2017.01.19 12:30:00':'2017.01.19 15:10:00']]， 我收到Must pass DataFrame with boolean values only错误.

If I try: df[df['2017.01.19 12:30:00':'2017.01.19 15:10:00']], I get the Must pass DataFrame with boolean values only error.

因此，请帮助我，让我知道如何基于索引的DateTime过滤器设置列的值.

So please help me and let me know how to set the value of a column based on an indexed DateTime filter.

谢谢.

推荐答案

使用 DataFrame.loc ，日期时间与-代替，.:

df.loc['2017-01-19 12:30:00':'2017-01-19 15:10:00', "column_value"] = "something"

示例:

idx =  pd.date_range('2017-01-19 12:00:00', '2017-01-19 16:30:00', freq='10T')
df = pd.DataFrame({'column_value': ['a'] * len(idx)}, index = idx)

df.loc['2017-01-19 12:30:00':'2017-01-19 15:10:00', "column_value"] = "something"
print (df)
                    column_value
2017-01-19 12:00:00            a
2017-01-19 12:10:00            a
2017-01-19 12:20:00            a
2017-01-19 12:30:00    something
2017-01-19 12:40:00    something
2017-01-19 12:50:00    something
2017-01-19 13:00:00    something
2017-01-19 13:10:00    something
2017-01-19 13:20:00    something
2017-01-19 13:30:00    something
2017-01-19 13:40:00    something
2017-01-19 13:50:00    something
2017-01-19 14:00:00    something
2017-01-19 14:10:00    something
2017-01-19 14:20:00    something
2017-01-19 14:30:00    something
2017-01-19 14:40:00    something
2017-01-19 14:50:00    something
2017-01-19 15:00:00    something
2017-01-19 15:10:00    something
2017-01-19 15:20:00            a
2017-01-19 15:30:00            a
2017-01-19 15:40:00            a
2017-01-19 15:50:00            a
2017-01-19 16:00:00            a
2017-01-19 16:10:00            a
2017-01-19 16:20:00            a
2017-01-19 16:30:00            a

这篇关于根据索引的日期时间过滤器设置列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！