Python堆栈数据帧

Question

这是货车、卡车每小时交通量计数的数据帧：

方向>卡车<1><2>

日期	小时	货车
2019-02-01		0	EB
2019-02-01	0	WB	3	4

set_index然后堆栈：

import pandas as pd
df = pd.DataFrame({
'Date': {0: '2019-02-01', 1: '2019-02-01'}, 'Hour': {0: 0, 1: 0},
'Direction': {0: 'EB', 1: 'WB'}, 'Van': {0: 1, 1: 3}, 'Truck': {0: 2, 1: 4}
})
stacked = df.set_index(['Date', 'Hour', 'Direction']).stack() 
.reset_index().rename(columns={'level_3': 'Class', 0: 'Count'})
print(stacked)

stacked:

Date  Hour Direction  Class  Count
0  2019-02-01     0        EB    Van      1
1  2019-02-01     0        EB  Truck      2
2  2019-02-01     0        WB    Van      3
3  2019-02-01     0        WB  Truck      4

或熔化：

melted = df.melt(id_vars=['Date', 'Hour', 'Direction'],
var_name='Class',
value_name='Count')
print(melted)

melted:

Date  Hour Direction  Class  Count
0  2019-02-01     0        EB    Van      1
1  2019-02-01     0        WB    Van      3
2  2019-02-01     0        EB  Truck      2
3  2019-02-01     0        WB  Truck      4