pandas 将数据框列中的日期转换为 MM/DD/YYYY
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Conversion of dates in the dataframe column into MM/DD/YYYY
提问by User1090
I have 4 dataframes named df1,df2,df3,df4with one column Date. The column consist of dates with different format. df1has date column of type int64, df2has date column of type object, df3has date column has type object, df4has date column of type object. Below are the dataframe and its data.
我有 4 个名为df1, df2, 的数据框df3，df4其中有一列Date。该列由不同格式的日期组成。df1具有类型为 int64 的df2日期列，具有类型为对象的df3日期列，具有类型为对象的日期列，具有类型为对象的df4日期列。以下是数据框及其数据。
df1:
Date
0 20160301
1 20160301
2 20160301
3 20160301
df2:
Date
0 01/03/2016
1 01/03/2016
2 01/03/2016
df3:
Date
0 31-Mar-16
1 31-Mar-16
2 31-Mar-16
df4:
Date
0 25/02/2016
1 25/02/2016
2 25/02/2016
I want to convert these dates in the form as mm/dd/yyyyof type date. Can anyone help me on this?
我想以mm/dd/yyyytype的形式转换这些日期date。谁可以帮我这个事？
回答by jezrael
I think you can use to_datetimeand dt.strftime, but typeis not datetime, but string:
我认为您可以使用to_datetimeand dt.strftime，但type不是datetime，但是string：
df1['Date'] = pd.to_datetime(df1['Date'], format='%Y%m%d').dt.strftime('%m/%d/%Y')
df2['Date'] = pd.to_datetime(df2['Date']).dt.strftime('%m/%d/%Y')
df3['Date'] = pd.to_datetime(df3['Date']).dt.strftime('%m/%d/%Y')
df4['Date'] = pd.to_datetime(df4['Date']).dt.strftime('%m/%d/%Y')
print df1
print df2
print df3
print df4
Date
0 03/01/2016
1 03/01/2016
2 03/01/2016
3 03/01/2016
Date
0 01/03/2016
1 01/03/2016
2 01/03/2016
Date
0 03/31/2016
1 03/31/2016
2 03/31/2016
Date
0 02/25/2016
1 02/25/2016
2 02/25/2016
print type(df1.at[0,'Date'])
<type 'str'>
If you want datetime, format is YY-MM-DD:
如果需要datetime，格式为YY-MM-DD：
df1['Date'] = pd.to_datetime(df1['Date'], format='%Y%m%d')
df2['Date'] = pd.to_datetime(df2['Date'])
df3['Date'] = pd.to_datetime(df3['Date'])
df4['Date'] = pd.to_datetime(df4['Date'])
print df1
print df2
print df3
print df4
Date
0 2016-03-01
1 2016-03-01
2 2016-03-01
3 2016-03-01
Date
0 2016-01-03
1 2016-01-03
2 2016-01-03
Date
0 2016-03-31
1 2016-03-31
2 2016-03-31
Date
0 2016-02-25
1 2016-02-25
2 2016-02-25
print type(df1.at[0,'Date'])
<class 'pandas.tslib.Timestamp'>
More info about formating datetimeis here.
有关格式化更多信息datetime是在这里。
