python提取指定行和列的數據，python dataframe 取一行_python – Pandas dataframe獲取每個組的第一行

我有一個pandas DataFrame如下。

df = pd.DataFrame({'id' : [1,1,1,2,2,3,3,3,3,4,4,5,6,6,6,7,7],

'value' : ["first","second","second","first",

"second","first","third","fourth",

python提取指定行和列的數據？"fifth","second","fifth","first",

"first","second","third","fourth","fifth"]})

我想通過[“id”，“value”]分組，并得到每個組的第一行。

id value

0 1 first

python菜鳥教程。1 1 second

2 1 second

3 2 first

4 2 second

5 3 first

DataFrame對某一列進行運算、6 3 third

7 3 fourth

8 3 fifth

9 4 second

10 4 fifth

formdata、11 5 first

12 6 first

13 6 second

14 6 third

15 7 fourth

python二維list取某一列？16 7 fifth

預期結果

id value

1 first

2 first

pandas DataFrame，3 first

4 second

5 first

6 first

7 fourth

python如何按行輸出列表。我試著下面只給出DataFrame的第一行。任何幫助，這是贊賞。

In [25]: for index, row in df.iterrows():

....: df2 = pd.DataFrame(df.groupby(['id','value']).reset_index().ix[0])