问题描述
我有以下包含数千行的 Pandas 数据框:
import pandas
...
print(df)
FAVORITE_FOOD FAVORITE_DRINK ... USER_A USER_B
0 hamburgers cola ... John John
1 pasta lemonade ... John John
2 omelette coffee ... John John
3 hotdogs beer ... Marie Marie
4 pizza wine ... Marie Marie
7 popcorn oj ... Adam Adam
8 sushi sprite ... Adam Adam
...
...
我想创建一个嵌套字典,其中人名是键,他们的食物/饮料组合字典是值。
像这样:
dict = {John : {hamburgers : cola,pasta : lemonade,omelette : coffee},Marie : {hotdogs : beer,pizza : wine},Adam : {popcorn : oj,sushi : sprite}
}
解决方法
您可以通过以下方式创建所需的字典
dict1 = {} for i in range(len(df)): row = df.iloc[i,:] dict1.setdefault(row["USER_A"],{}).update({row["FAVORITE_FOOD"] : row["FAVORITE_DRINK"]})
我使用 setdefault
方法最初创建空字典,然后附加其他字典作为值。
我用下面的代码解决了这个问题:
import pandas as pd
# this line groups user ID with their favorite food and drink
group_dict = {k: f.groupby('FAVORITE_FOOD')['FAVORITE_DRINK'].apply(list).to_dict() for k,f in df.groupby('USER_A')}
# then we use dictionary comprehension to create the desired nested dictionary
nested_dict = {outer_k: {inner_k : {inner_v for inner_v in v if inner_k != inner_v} for inner_k,v in outer_v.items()} for outer_k,outer_v in group_dict.items()}