如何在 Pandas 中按降序对两列进行排序？
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How to Sort Two Columns by Descending Order in Pandas?
提问by MEhsan
I have this dataframe dfconsisting of two columns IDand Date:
我有这个数据框df由两列ID和Date：
ID Date
4 1/1/2008
3 1/1/2007
2 9/23/2010
2 6/3/1998
2 1/1/2001 # Note this date should be before "6/3/1998" for ID# 2
1 4/30/2003
I want to sort dfby IDand Datein descending order (largest --> smallest), but this seems not working when I tried the following script:
我要排序df的ID和Date降序排列（最大- >最小的），但是这似乎当我尝试下面的脚本不工作：
print df.sort_values(by=["ID", "Date"], ascending=["False", "False"])
The output should in this descending order:
输出应按此降序排列：
ID Date
4 1/1/2008
3 1/1/2007
2 9/23/2010
2 1/1/2001
2 6/3/1998
1 4/30/2003
Any idea how can I sort the date in the correct descending order?
知道如何按正确的降序对日期进行排序吗？
回答by RAVI
You will first need to convert type of Date column from String to Date.
您首先需要将日期列的类型从字符串转换为日期。
df['Date'] = pd.to_datetime(df['Date'], format="%m/%d/%Y")
Now you can use df.sort_values
现在你可以使用df.sort_values
print df.sort_values(by=["ID", "Date"], ascending=[False, False])
Output :
输出 ：
ID Date
0 4 2008-01-01
1 3 2007-01-01
2 2 2010-09-23
4 2 2001-01-01
3 2 1998-06-03
5 1 2003-04-30
In your code, for ascending argument you are passing string "False", but it should be bool False
在您的代码中，对于升序参数，您正在传递 string "False"，但它应该是 boolFalse
