Python pandas

日期字符串提取月份

import pandas as pd
data = {
    'date':['2022-01-6','2021-1-15','2020-12-5','2022-09-23'],
    'value':[1,4,54,5454]
}
df = pd.DataFrame(data)

    date        value
0   2022-01-6   1
1   2021-1-15   4
2   2020-12-5   54
3   2022-09-23  5454

1 转换为日期格式

df['date1'] = pd.to_datetime(df['date'],format='%Y-%m-%d').dt.strftime('%Y-%m')

2 正则表达式

df['date3'] = df['date'].str.replace('(\d+)-(\d+)-(\d+)',r'\1-\2')

    date    value   date1   date2   date3
0   2022-01-6   1   2022-01-06  2022-01 2022-01
1   2021-1-15   4   2021-01-15  2021-01 2021-1
2   2020-12-5   54  2020-12-05  2020-12 2020-12
3   2022-09-23  5454    2022-09-23  2022-09 2022-09

重命名索引列名

df.index.name = 'newIndex'