如何使用Python从购买地址列中提取城市

import re
import pandas as pd

def extract_city(address):
    pattern = r',\s*([A-Za-z\s]+),'
    match = re.search(pattern, address)
    if match:
        return match.group(1)
    else:
        return None

data = {'购买地址': ['123 Main St, New York, NY 10001', '456 Elm St, Los Angeles, CA 90001', '789 Oak St, Chicago, IL 60601']}
df = pd.DataFrame(data)

df['城市'] = df['购买地址'].apply(extract_city)

print(df)

                             购买地址           城市
0    123 Main St, New York, NY 10001     New York
1  456 Elm St, Los Angeles, CA 90001  Los Angeles
2      789 Oak St, Chicago, IL 60601      Chicago