Python Pandas - 根据要匹配到列名的另一个表的值切片 DataFrame

Question

I have two dataframes, df_stats and df_ratings.

df_stats looks like this

	Fruit	Rating_Threshold_Low	Rating_Threshold_High
1	Apple	4	7
2	Banana	5	9
3	Kiwi	6	8

df_ratings looks like this (the first column is the Fruit and each subsequent column represents a rating .

	Fruit	1	2	3	4	5	6	7	8	9	10
1	Apple	2	4	7	13	2	0	16	1	9	22
2	Banana	6	4	2	1	8	7	5	3	9	0
3	Kiwi	21	4	3	6	8	9	9	8	7	5

What my goal is to get the sum of each the number of ratings within the rating threshold for each fruit (each fruit's rating threshold is different). In other words, I want to add the column, Rating_Threshold_Sum in df_stats , which computes the sum of the ratings within the threshold df_ratings . For example, for Apple , the Rating threshold is between 4 and 7 (inclusive), so the Rating_Threshold_Sum would be 13+2+0+16 = 31.

So as a result, df_stats would have the Ratings_Threshold_Sum column:

	Fruit	Rating_Threshold_Low	Rating_Threshold_High	Rating_Threshold_Sum
1	Apple	4	7	31
2	Banana	5	9	32
3	Kiwi	6	8	26

I am not sure how to exactly do that, I know that I may have to use df.apply with a custom function, or looping through each row, but aside from that, I'm not sure the best way to tackle this problem. Any advice / direction would be much appreciated. Thank you!

Answer 1

You could do something like this

sums = []
for i in range(len(df_stats)):
   min_v, max_v = df_stats["Rating_Threshold_Low"].values()[i], df_stats["Rating_Threshold_High"].values()[i]  
   values = []
   for z in range(min_v, max_v+1):
      x = df_ratings[str(z)][i]
      values.append(x)
   sums.append(sum(values))
df_stats["Rating_Threshold_Sum"] = sums

This is really complicated and there is probably a better way to do it but it should work.