计算 pandas 数据框设置的范围内的日期 [英] Counting dates in a range set by pandas dataframe

问题描述

我有一个熊猫数据框，其中包含两个日期列，一个开始日期和一个定义范围的结束日期。我希望能够收集这些列所定义的数据框中所有行的所有日期的总数。

I have a pandas dataframe that contains two date columns, a start date and an end date that defines a range. I'd like to be able to collect a total count for all dates across all rows in the dataframe, as defined by these columns.

例如，表看起来像：

index        start_date         end date
     0         '2015-01-01'    '2015-01-17'
     1         '2015-01-03'    '2015-01-12'

结果是每个日期的总计，例如：

And the result would be a per date aggregate, like:

    date           count
'2015-01-01'     1
'2015-01-02'     1
'2015-01-03'     2

我当前的方法有效，但是在大数据帧上却非常慢，因为我要遍历行，计算范围然后遍历。我希望找到一种更好的方法。

My current approach works but is extremely slow on a big dataframe as I'm looping across the rows, calculating the range and then looping through this. I'm hoping to find a better approach.

当前我正在做的事情：

date = pd.date_range (min (df.start_date), max (df.end_date))
df2 = pd.DataFrame (index =date)
df2 ['count'] = 0

for index, row in df.iterrows ():
    dates = pd.date_range (row ['start_date'], row ['end_date'])
    for date in dates:
        df2.loc['date']['count'] += 1

推荐答案

按照@Sam的建议堆叠相关列后，只需使用 value_counts 。

After stacking the relevant columns as suggested by @Sam, just use value_counts.

df[['start_date', 'end date']].stack().value_counts()

编辑：

鉴于您还希望计算开始日期和结束日期之间的日期：

Given that you also want to count the dates between the start and end dates:

start_dates = pd.to_datetime(df.start_date)
end_dates = pd.to_datetime(df.end_date)

>>> pd.Series(dt.date() for group in 
              [pd.date_range(start, end) for start, end in zip(start_dates, end_dates)]  
              for dt in group).value_counts()
Out[178]: 
2015-01-07    2
2015-01-06    2
2015-01-12    2
2015-01-05    2
2015-01-04    2
2015-01-10    2
2015-01-03    2
2015-01-09    2
2015-01-08    2
2015-01-11    2
2015-01-16    1
2015-01-17    1
2015-01-14    1
2015-01-15    1
2015-01-02    1
2015-01-01    1
2015-01-13    1
dtype: int64

这篇关于计算 pandas 数据框设置的范围内的日期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！