我想在total
中插入一个名为final_df
的新列,如果它在{{1}中的时间之间发生,则是value
在df
中的累积总和。 }。如果它出现在final_df
中的start
和end
之间,则将这些值相加。因此,例如,在final_df
中的01:30到02:00的时间范围内– final_df
中的索引0和1都出现在该时间范围之间,因此总数为15(10 + 5)。>
我有两个熊猫数据框:
df
df
final_df
import pandas as pd
d = {'start_time': ['01:00','00:00','00:30','02:00'],
'end_time': ['02:00','03:00','01:30','02:30'],
'value': ['10','5','20','5']}
df = pd.DataFrame(data=d)
我想要的输出final_df
final_d = {'start_time': ['00:00, 00:30, 01:00, 01:30, 02:00, 02:30'],
'end_time': ['00:30, 01:00, 01:30, 02:00, 02:30, 03:00']}
final_df = pd.DataFrame(data=final_d)
我的尝试
start_time end_time total
00:00 00:30 5
00:30 01:00 25
01:00 01:30 35
01:30 02:00 15
02:30 03:00 10
问题1
我收到错误消息:TypeError:('str'和'datetime.time'','发生在索引0'的实例之间不支持“”> =')
我将相关列转换为日期时间,如下所示:
final_df['total'] = final_df.apply(lambda x: df.loc[(df['start_time'] >= x.start_time) &
(df['end_time'] <= x.end_time), 'value'].sum(), axis=1)
但是我不想转换为日期时间。有办法解决吗?
问题2
总和不能正常工作。它只是在寻找时间范围内的精确匹配。所以输出是:
df[['start_time','end_time']] = df[['start_time','end_time']].apply(pd.to_datetime, format='%H:%M')
final_df[['start_time','end_time']] = final_df[['start_time','end_time']].apply(pd.to_datetime, format='%H:%M:%S')
答案 0 :(得分:2)
不使用apply
的一种方法可能是这样的。
df_ = (df.rename(columns={'start_time':1, 'end_time':-1}) #to use in the calculation later
.rename_axis(columns='mult') # mostly for esthetic
.set_index('value').stack() #reshape the data
.reset_index(name='time') # put the index back to columns
)
df_ = (df_.set_index(pd.to_datetime(df_['time'], format='%H:%M')) #to use resampling technic
.assign(total=lambda x: x['value'].astype(float)*x['mult']) #get plus or minus the value depending start/end
.resample('30T')[['total']].sum() # get the sum at the 30min bounds
.cumsum() #cumulative sum from the beginning
)
# create the column for merge with final resul
df_['start_time'] = df_.index.strftime('%H:%M')
# merge
final_df = final_df.merge(df_)
你会得到
print (final_df)
start_time end_time total
0 00:00 00:30 5.0
1 00:30 01:00 25.0
2 01:00 01:30 35.0
3 01:30 02:00 15.0
4 02:00 02:30 10.0
5 02:30 03:00 5.0
但是,如果要使用apply,首先需要确保列是良好的dtype,然后按照相反的顺序进行平整化,例如:
df['start_time'] = pd.to_datetime(df['start_time'], format='%H:%M')
df['end_time'] = pd.to_datetime(df['end_time'], format='%H:%M')
df['value'] = df['value'].astype(float)
final_df['start_time'] = pd.to_datetime(final_df['start_time'], format='%H:%M')
final_df['end_time'] = pd.to_datetime(final_df['end_time'], format='%H:%M')
final_df.apply(
lambda x: df.loc[(df['start_time'] <= x.start_time) & #see other inequality
(df['end_time'] >= x.end_time), 'value'].sum(), axis=1)
0 5.0
1 25.0
2 35.0
3 15.0
4 10.0
5 5.0
dtype: float64