pandas 某一列分组，其他列合并成list

pandas列转换为字典，但将相同第一列（键）的所有值合并为一个键

 

形式一： 

import pandas as pd

# data
data = pd.DataFrame({'column1':['key1','key1','key2','key2'],
       'column2':['value1','value2','value3','value3']})
print(data)

# Grouped dict
data_dict = data.groupby('column1').column2.apply(list).to_dict() 

print(data_dict)

输出结果：
  column1 column2
0    key1  value1
1    key1  value2
2    key2  value3
3    key2  value3

{'key1': ['value1', 'value2'], 'key2': ['value3', 'value3']}

形式二：

import pandas as pd
# data
df = pd.DataFrame({'column1':['key1','key1','key2','key2'],
       'column2':['value1','value2','value1','value2'],
       'column3':['value11','value11','value22','value22'],
       'column4':['value44','value44','value55','value55']})

# Grouped dict
data_dict = df.groupby('column1').apply(lambda x: {col:x[col].tolist() for col in x.columns if col != 'column2'}).to_dict()
print(data_dict)

data_dict2 = df.groupby('column1').apply(lambda x: {col:x[col].tolist()[0] if col != 'column2' else x[col].tolist() for col in x.columns}).to_dict()
print(data_dict2)

输出结果：
#data_dict
{
    'key1': {
        'column1': ['key1', 'key1'], 
        'column3': ['value11', 'value11'], 
        'column4': ['value44', 'value44']
    }, 
    'key2': {
        'column1': ['key2', 'key2'], 
        'column3': ['value22', 'value22'], 
        'column4': ['value55', 'value55']
    }
}
#data_dict2
{
    'key1': {
        'column1': 'key1', 
        'column2': ['value1', 'value2'], 
        'column3': 'value11', 
        'column4': 'value44'
    }, 
    'key2': {
        'column1': 'key2', 
        'column2': ['value1', 'value2'], 
        'column3': 'value22', 
        'column4': 'value55'
    }
}