pandas 循环遍历列并在特定条件下停止（python）
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Loop through column and stop at a certain condition (python)
提问by Erin
I have a dataframe similar to below,
我有一个类似于下面的数据框，
Date A B
2017-01-01 1 1
2017-01-02 2 2
2017-01-03 1 2
For each column, I want to test the condition A==B for each name in the groupby statement. If this condition does not hold true, I want to print "Condition ends at 2017-01-03." I'm not sure how to loop through each row in this dataframe. I'm envisioning something like this code, although I know I am not itterating through the correct thing:
对于每一列，我想测试 groupby 语句中每个名称的条件 A==B。如果此条件不成立，我想打印“条件结束于 2017-01-03”。我不确定如何遍历此数据框中的每一行。我正在设想类似这样的代码，尽管我知道我没有通过正确的事情进行迭代：
for i in df.Date:
if df.A == df.B:
continue
if df.A != df.B:
print ("Condition ends at", i)
回答by zillaofthegods
回答by Evan Nowak
You could do it like this:
你可以这样做：
print 'Condition ends at', (df.A.values != df.B.values).argmax()
回答by maor10
You could use the nice pythonic syntax:
您可以使用漂亮的 pythonic 语法：
print next([d for d in dates if d.A != d.B], None)
The None would be the default value if none is found
如果没有找到，则 None 将是默认值
