使用 pandas 将多列插入单列

Question

I am converting a SAS code to python and got stuck here.

My input table is like:-

St	sgmt	Val
A	CD	200
A	PQ	300

My output should be like:-

Col	Val
A	500
CD	200
PQ	300

500 is the sum of values of same category

Answer 1

You can melt to combine the "St" and "sgmt" columns, then GroupBy.sum to aggregate per name:

(df
 .melt('Val', value_name='Col')
 .groupby('Col', as_index=False)
 ['Val'].sum()
)

output:

  Col  Val
0   A  500
1  CD  200
2  PQ  300