python - 处理闰年并替换新日期

Question

我在列名称 DATE 下的 python 数据框 (df) 中有一个日期列表:

0       1998-03-31
1       1998-06-30
2       1998-09-30
3       1998-12-31
4       1999-03-31
5       1999-06-30
6       1999-09-30
7       1999-12-31
8       2000-02-29
9       2000-06-30
10      2000-09-30
11      2000-12-31
12      2001-03-31
13      2001-06-30
14      2001-09-30
Name: DATE, dtype: datetime64[ns]

我想将所有闰年日期 XXXX-02-29 变成 XXXX-02-28。最有效的方法是什么？谢谢。

Answer 1

这可以通过 pd.datetime 和 lambda apply 来完成:

import pandas as pd

# Make DataFrame
df = pd.DataFrame(
    pd.date_range('1998-02-28', periods=12, freq='6M'), 
    columns=['Date']
)
print 'Original DataFrame:'
print df
print

# Replace feb 29 with feb 28
df['Date'] = df['Date'].apply(
    lambda x: 
        x if x.month != 2 and x.date != 29 
        else pd.datetime(x.year, x.month, 28)
)

print 'Processed DataFrame:'
print df
print

---

Original DataFrame:
         Date
0  1998-02-28
1  1998-08-31
2  1999-02-28
3  1999-08-31
4  2000-02-29
5  2000-08-31
6  2001-02-28
7  2001-08-31
8  2002-02-28
9  2002-08-31
10 2003-02-28
11 2003-08-31

Processed DataFrame:
         Date
0  1998-02-28
1  1998-08-31
2  1999-02-28
3  1999-08-31
4  2000-02-28
5  2000-08-31
6  2001-02-28
7  2001-08-31
8  2002-02-28
9  2002-08-31
10 2003-02-28
11 2003-08-31