[英]Pandas Create a column with the a sum of a nested dataframe column
如何使用來自嵌套數據幀的值的總和將新列添加到數據幀,而不會丟失任何其他列和使用 Pandas 的嵌套數據?
具體來說,我想創建一個新列total_cost
,其中包含一行的所有嵌套數據幀的總和。
我設法使用一系列groupby
和apply
創建了以下數據groupby
:
user_id description unit_summary
0 111 xxx [{'total_period_cost': 100, 'unit_id': 'xxx', ...
1 222 xxx [{'total_period_cost': 100, 'unit_id': 'yyy', ...
我正在嘗試添加列total_cost
,它是每個嵌套數據幀的total_period_cost
的總和(按user_id
分組)。 如何實現以下數據框?
user_id description total_cost unit_summary
0 111 xxx 300 [{'total_period_cost': 100, 'unit_id': 'xxx', ...
1 222 xxx 100 [{'total_period_cost': 100, 'unit_id': 'yyy', ...
import pandas as pd
series = [{
"user_id":"111",
"description": "xxx",
"unit_summary":[
{
"total_period_cost":100,
"unit_id":"xxx",
"cost_per_unit":50,
"total_period_usage":2
},
{
"total_period_cost":200,
"unit_id":"yyy",
"cost_per_unit":25,
"total_period_usage": 8
}
]
},
{
"user_id":"222",
"description": "xxx",
"unit_summary":[
{
"total_period_cost":100,
"unit_id":"yyy",
"cost_per_unit":25,
"total_period_usage": 4
}
]
}]
df = pd.DataFrame(series)
print(df)
print(df.to_dict(orient='records'))
series
JSON 對象的 groupby..apply 代碼示例:import pandas as pd
series = [
{"user_id":"111", "unit_id":"xxx","cost_per_unit":50, "total_period_usage": 1},
{"user_id":"111", "unit_id":"xxx","cost_per_unit":50, "total_period_usage": 1},
{"user_id":"111", "unit_id":"yyy","cost_per_unit":25, "total_period_usage": 8},
{"user_id":"222", "unit_id":"yyy","cost_per_unit":25, "total_period_usage": 3},
{"user_id":"222", "unit_id":"yyy","cost_per_unit":25, "total_period_usage": 1}
]
df = pd.DataFrame(series)
sumc = (
df.groupby(['user_id', 'unit_id', 'cost_per_unit'], as_index=False)
.agg({'total_period_usage': 'sum'})
)
sumc['total_period_cost'] = sumc.total_period_usage * sumc.cost_per_unit
sumc = (
sumc.groupby(['user_id'])
.apply(lambda x: x[['total_period_cost', 'unit_id', 'cost_per_unit', 'total_period_usage']].to_dict('r'))
.reset_index()
)
sumc = sumc.rename(columns={0:'unit_summary'})
sumc['description'] = 'xxx'
print(sumc)
print(sumc.to_dict(orient='records'))
def myf(x):
return pd.DataFrame(x).loc[:,'total_period_cost'].sum()
# Sum all server sumbscriptions total_period_cost
sumc['total_period_cost'] = sumc['unit_summary'].apply(myf)
您可以將unit_summary
列中的每一行讀取為數據unit_summary
並對所需的列求和:
方法一: apply
def myf(x):
return pd.DataFrame(x).loc[:,'total_period_cost'].sum()
df['total_cost'] = df['unit_summary'].apply(myf)
print(df)
方法2:同樣通過列表理解:
df['total_cost'] = [pd.DataFrame(i)['total_period_cost'].sum()
for i in df['unit_summary'].tolist()]
方法3:使用explode
:
m = df['unit_summary'].explode()
df['total_cost'] = pd.DataFrame(m.tolist(),index=m.index)['total_period_cost'].sum(level=0)
user_id description unit_summary \
0 111 xxx [{'total_period_cost': 100, 'unit_id': 'xxx', ...
1 222 xxx [{'total_period_cost': 100, 'unit_id': 'yyy', ...
total_cost
0 300
1 100
除了上述之外,從您的原始數據幀開始,我們還可以執行以下操作來實現所需的輸出,但這不會為您提供帶有 dicts ('unit_summary`) 的系列:
(df.assign(total_cost=df['cost_per_unit']*df['total_period_usage'])
.groupby(['user_id'],as_index=False)['total_cost'].sum().assign(description='xxxx'))
user_id total_cost description
0 111 300 xxxx
1 222 100 xxxx
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