我有两个包含道路事故信息的大数据帧(以下只是摘录(,其中df_veh
包含车辆的详细信息,df_ped
包含每次事故中涉及的行人数量。veh_type
显示了事故中涉及的车辆类型(1=自行车,2=汽车,3=公共汽车(。它们与acc_index
相连,表示发生了独特的事故。
veh_data = {'acc_index': ['001', '002', '002', '003', '003', '004', '005', '005', '006',
'006', '007', '007', '008', '008', '008', '009', '009', '009'],
'veh_type': ['1', '1', '2', '1', '1', '1', '2', '2', '2', '3', '1', '2', '1', '1',
'1', '1', '2', '2'] }
df_veh = pd.DataFrame (veh_data, columns = ['acc_index', 'veh_type'])
ped_data = {'acc_index': ['001', '002', '003', '004', '005', '006', '007', '008', '009'],
'pedestrians': ['1', '2', '0', '1', '4', '3', '0', '1', '2'] }
df_ped = pd.DataFrame (ped_data, columns = ['acc_index', 'pedestrians'])
我想做的是统计事故数量(由UNIQUEacc_index
仅一次(:
- 在汽车和自行车之间(
veh_type==1
和veh_type==2
( - 自行车和行人之间(
veh_type==1
和pedestrians>=1
( - 汽车和行人之间(
veh_type==2
和pedestrians>=1
( - 仅在辆车之间(同一acc_index的
veh_type==2
( - 在仅自行车之间(
veh_type==1
用于相同的acc_index( - 仅行人之间(同一acc_index的
pedestrians>=1
(
我试着用不同的方式做,但最终,我得到了不同的结果,所以我很困惑。例如,我试着统计这样的自行车行人事故:
df_bikes = df_veh[df_veh['veh_type']==1].groupby('acc_index').sum().reset_index()
bike_ped = pd.merge(df_bikes, df_ped, how='outer', on='acc_index')
bike_ped[(bike_ped['veh_type']==1) & (bike_ped['pedestrians']>=1)].groupby(
'acc_index').sum().reset_index()[['acc_index', 'veh_type', 'pedestrians']]
另一个例子,这是我如何计算汽车和自行车之间的事故感谢在这篇文章中的评论。我相信这个至少是正确的。我正试图找到最简单的方法来做到这一点(但也显示已计数的行(。
bike_car = df_veh[def_veh.groupby('acc_index')['veh_type'].
transform(lambda g: not({1, 2} - {*g}))][['acc_index', 'veh_type']]
len(bike_car.groupby(['acc_index']).size().reset_index()))
考虑使用与行人的groupby
集合连接的pivot_table
来调整车辆数据,然后运行所需的query()
调用,其中每行都是不同的acc_index
:
veh_dict = {'1': 'bicycle', '2': 'car', '3': 'bus'}
pvt_df = (df_veh.assign(val = 1)
.pivot_table(index = 'acc_index',
columns = 'veh_type',
values = 'val',
aggfunc='sum')
.set_axis([veh_dict[i] for i in list('123')],
axis = 'columns',
inplace = False)
.join(df_ped.assign(pedestrians = lambda x: x['pedestrians'].astype('int'))
.groupby('acc_index')['pedestrians']
.sum()
.to_frame(),
how = 'outer'
)
)
pvt_df
# bicycle car bus pedestrians
# acc_index
# 001 1.0 NaN NaN 1
# 002 1.0 1.0 NaN 2
# 003 2.0 NaN NaN 0
# 004 1.0 NaN NaN 1
# 005 NaN 2.0 NaN 4
# 006 NaN 1.0 1.0 3
# 007 1.0 1.0 NaN 0
# 008 3.0 NaN NaN 1
# 009 1.0 2.0 NaN 2
查询
# BIKES AND CARS
pvt_df.query('(bicycle >= 1) & (car >= 1)')
# bicycle car bus pedestrians
# acc_index
# 002 1.0 1.0 0.0 2
# 007 1.0 1.0 0.0 0
# 009 1.0 2.0 0.0 2
# BIKES AND PEDESTRIANS
pvt_df.query('(bicycle >= 1) & (pedestrians >= 1)')
# bicycle car bus pedestrians
# acc_index
# 001 1.0 0.0 0.0 1
# 002 1.0 1.0 0.0 2
# 004 1.0 0.0 0.0 1
# 008 3.0 0.0 0.0 1
# 009 1.0 2.0 0.0 2
# CARS AND PEDESTRIANS
pvt_df.query('(car >= 1) & (pedestrians > 1)')
# bicycle car bus pedestrians
# acc_index
# 002 1.0 1.0 0.0 2
# 005 0.0 2.0 0.0 4
# 006 0.0 1.0 1.0 3
# 009 1.0 2.0 0.0 2
### ONLY CARS
pvt_df.query('(bicycle == 0) & (car >= 1) & (bus == 0) & (pedestrians == 0)')
# Empty DataFrame
# Columns: [bicycle, car, bus, pedestrians]
# Index: []
### ONLY BICYCLES
pvt_df.query('(bicycle >= 1) & (car == 0) & (bus == 0) & (pedestrians == 0)')
# bicycle car bus pedestrians
# acc_index
# 003 2.0 0.0 0.0 0
### ONLY PEDESTRIANS
pvt_df.query('(bicycle == 0) & (car == 0) & (bus == 0) & (pedestrians >= 1)')
# Empty DataFrame
# Columns: [bicycle, car, bus, pedestrians]
# Index: []