合并数据帧列表并对不同列求和

I have a list of dataframes

我有一个数据帧列表

> df.t
[[1]]
column_A start_B stop_C column_D column_E
1        0        23       2        3 
1        23       200      1        0
2        0        55       0        1
[[2]]
column_A start_B stop_C column_D column_E
1        0        200      1        0
2        0        20       2        0
2        20       55       0        1
[[3]]
column_A start_B stop_C column_D column_E
1        0        200      0        0
2        0        55       4        2
> df.