使用groupby将dataframe转换为dict

import pandas as pd

# 创建一个示例 DataFrame
data = {
    'Name': ['Alice', 'Bob', 'Charlie', 'David', 'Eva'],
    'City': ['New York', 'Los Angeles', 'New York', 'Chicago', 'Los Angeles'],
    'Age': [25, 30, 35, 40, 45]
}
df = pd.DataFrame(data)

# 使用 groupby 将 DataFrame 转换为 dict
grouped_dict = df.groupby('City')['Name'].apply(list).to_dict()

print(grouped_dict)

{
    'New York': ['Alice', 'Charlie'],
    'Los Angeles': ['Bob', 'Eva'],
    'Chicago': ['David']
}

if 'City' in df.columns:
    grouped_dict = df.groupby('City')['Name'].apply(list).to_dict()
else:
    print("Column 'City' does not exist in DataFrame.")

df['City'] = df['City'].astype(str)  # 确保 'City' 列是字符串类型
grouped_dict = df.groupby('City')['Name'].apply(list).to_dict()