如何在for循环中检索Pandas GroupBy对象的行 [英] How to retrieve rows of a Pandas GroupBy object in for loop

问题描述

我有一个按对象分组.我想在for循环&中检索按对象分组的特定列的行.做一些处理.例如，我在这里给出了按对象分组的示例代码

I have a group by object.I want to retrieve rows of a particular column of the group by object in for loop & do some processing. For example,I'm giving here a sample code for group by object

df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
                             'foo', 'bar', 'foo', 'foo'],
                       'B' : ['one', 'one', 'two', 'three',
                              'two', 'two', 'one', 'three'],
                       'C' : np.random.randn(8),
                       'D' : np.random.randn(8)})
grouped = df.groupby(['A', 'B'])

分组之后，我得到了追踪对象

After group by, I got following object

在for循环中，我想检查一下它是一个，两个还是三个&然后做一些处理.您能建议我一些步骤吗?

In a for loop I would like to do some check if it's one,two or three & then do some processing.Can you please suggest me the steps?

推荐答案

您可以像这样在group_by对象中循环:

you can loop in the group_by object like this :

for index, row in grouped:
    print (index) #index is a tuple 
    print(row) #row is a new dataframe 

要检查您要查找的内容，可以执行此操作(即:检查值是否在数据框的特定列中):

To check what you are looking for you can do this(ie: check if a value is in a certain column of a dataframe do this):

for index, row in grouped:
    if -0.83026 in row.get("C").values: # "C" or any column name you want
        print("hello")

对于您的数据，输出将如下所示:

for your data the output will be something like this :

('bar', 'one')
     A    B        C         D
1  bar  one -0.83026  0.983017
('bar', 'three')
     A      B         C         D
3  bar  three -0.381041  1.538971
('bar', 'two')
     A    B         C         D
5  bar  two -0.963402  0.201348
('foo', 'one')
     A    B         C         D
0  foo  one  0.691410  0.328420
6  foo  one -1.521541 -0.188345
('foo', 'three')
     A      B         C         D
7  foo  three -0.817304 -0.359331
('foo', 'two')
     A    B         C         D
2  foo  two -0.528639 -0.999301
4  foo  two -1.018919  0.661665

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