更改 pandas 日期格式以删除前导零的更好方法？

Question

DataFrame 看起来像：

       OPENED
0  2004-07-28
1  2010-03-02
2  2005-10-26
3  2006-06-30
4  2012-09-21

我成功地将它们转换成我想要的格式，但似乎效率很低。

我用于日期转换的代码是：

df['OPENED'] = pd.to_datetime(df.OPENED, format='%Y-%m-%d')
df['OPENED'] = df['OPENED'].apply(lambda x: x.strftime('%y%m%d'))
df['OPENED'] = df['OPENED'].apply(lambda i: str(i))
df['OPENED'] = df['OPENED'].apply(lambda s: s.lstrip("0"))

Answer 1

您可以使用 str.replace, then remove first 2 chars by str[2:] and last remove leading 0 by str.lstrip:

print (type(df.ix[0,'OPENED']))
<class 'str'>
print (df.OPENED.dtype)
object

print (df.OPENED.str.replace('-','').str[2:].str.lstrip('0'))
0     40728
1    100302
2     51026
3     60630
4    120921
Name: OPENED, dtype: object

如果 dtype 已经是 datetime 使用 strftime and str.lstrip:

print (type(df.ix[0,'OPENED']))
<class 'pandas.tslib.Timestamp'>
print (df.OPENED.dtype)
datetime64[ns]

print (df.OPENED.dt.strftime('%y%m%d').str.lstrip('0'))
0     40728
1    100302
2     51026
3     60630
4    120921
Name: OPENED, dtype: object

感谢的评论：

print (df['OPENED'].apply(lambda L: '{0}{1:%m%d}'.format(L.year % 100, L)))
0     40728
1    100302
2     51026
3     60630
4    120921
Name: OPENED, dtype: object

更改 pandas 日期格式以删除前导零的更好方法？

Better way to change pandas date format to remove leading zeros?

python

datetime

dataframe

pandas

leading-zero