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[英]Pandas: Create a new column based on a another column which is a list of objects
[英]pandas create a column based on values in another column which selected as conditions
我有以下df
,
id match_type amount negative_amount
1 exact 10 False
1 exact 20 False
1 name 30 False
1 name 40 False
1 amount 15 True
1 amount 15 True
2 exact 0 False
2 exact 0 False
我想創建一個列0_amount_sum
,指示(boolean)如果對於特定match_type
每個id, amount
和<= 0,例如,以下是結果df
;
id match_type amount 0_amount_sum negative_amount
1 exact 10 False False
1 exact 20 False False
1 name 30 False False
1 name 40 False False
1 amount 15 True True
1 amount 15 True True
2 exact 0 True False
2 exact 0 True False
對於id=1
和match_type=exact
, amount
總和為30,因此0_amount_sum
為False
。 代碼如下,
df = df.loc[df.match_type=='exact']
df['0_amount_sum_'] = (df.assign(
amount_n=df.amount * np.where(df.negative_amount, -1, 1)).groupby(
'id')['amount_n'].transform(lambda x: sum(x) <= 0))
df = df.loc[df.match_type=='name']
df['0_amount_sum_'] = (df.assign(
amount_n=df.amount * np.where(df.negative_amount, -1, 1)).groupby(
'id')['amount_n'].transform(lambda x: sum(x) <= 0))
df = df.loc[df.match_type=='amount']
df['0_amount_sum_'] = (df.assign(
amount_n=df.amount * np.where(df.negative_amount, -1, 1)).groupby(
'id')['amount_n'].transform(lambda x: sum(x) <= 0))
我想知道是否有更好的方法/更高效的方法,特別是當match_type
的值未知時,代碼可以自動枚舉所有可能的值,然后相應地進行計算。
我相信需要groupby
by 2 Series
(列)而不是過濾:
df['0_amount_sum_'] = ((df.amount * np.where(df.negative_amount, -1, 1))
.groupby([df['id'], df['match_type']])
.transform('sum')
.le(0))
id match_type amount negative_amount 0_amount_sum_
0 1 exact 10 False False
1 1 exact 20 False False
2 1 name 30 False False
3 1 name 40 False False
4 1 amount 15 True True
5 1 amount 15 True True
6 2 exact 0 False True
7 2 exact 0 False True
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