根据日期和字符串长度修改DataFrame中的数据

import pandas as pd
from datetime import datetime

data = {'日期': ['2022-01-01', '2022-02-01', '2022-03-01'],
        '字符串': ['abc', 'defg', 'hijkl']}
df = pd.DataFrame(data)

df['日期'] = pd.to_datetime(df['日期'])

df['字符串'] = df.apply(lambda row: row['字符串'].upper() if len(row['字符串']) > 3 else row['字符串'].lower(), axis=1)

print(df)

import pandas as pd
from datetime import datetime

data = {'日期': ['2022-01-01', '2022-02-01', '2022-03-01'],
        '字符串': ['abc', 'defg', 'hijkl']}
df = pd.DataFrame(data)

df['日期'] = pd.to_datetime(df['日期'])
df['字符串'] = df.apply(lambda row: row['字符串'].upper() if len(row['字符串']) > 3 else row['字符串'].lower(), axis=1)

print(df)