Python 如何从熊猫数据框中提取日期/年/月？
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How do I extract the date/year/month from pandas dataframe?
提问by Zhenyu Bo
I'm trying to extract year/date/month info from the 'date' column in pandas dataframe. Here is my sample code:
我正在尝试从 Pandas 数据框中的“日期”列中提取年/日/月信息。这是我的示例代码：
from datetime import datetime
def date_split(calendar):
for row in calendar:
new_calendar={}
listdate=datetime.strptime(row['date'],'%Y-%M-%D')
I haven't finished the complete code, but when i test run this part I keep getting error like this:
我还没有完成完整的代码，但是当我测试运行这部分时，我不断收到这样的错误：
----> 7 listdate=datetime.strptime(row['date'],'%Y-%M-%D')
TypeError: string indices must be integers
Anyone has any idea?
任何人有任何想法？
Btw, this is the dataframe I use (calendar_data):
顺便说一句，这是我使用的数据框（calendar_data）：
回答by jezrael
It seems you need to_datetime:
看来你需要to_datetime：
print (df['date'].dtype)
object
df['date'] = pd.to_datetime(df['date'])
print (df['date'].dtype)
datetime64[ns]
If need extract year, monthand dayto new columns:
df['year'] = df['date'].dt.year
df['month'] = df['date'].dt.month
df['day'] = df['date'].dt.day
If need listof dates:
如果需要list的dateS：
listdate = df['date'].dt.date.tolist()
print (listdate)
[datetime.date(2017, 9, 5),
datetime.date(2017, 9, 4),
datetime.date(2017, 9, 3),
datetime.date(2017, 9, 2),
datetime.date(2017, 9, 1)]
