相同的Dataframes斷言不等 - Python熊貓

我想單元測試我的代碼。我有一個給定MySQL查詢的方法，將結果作爲熊貓數據框返回。請注意，在數據庫中，created和external_id中的所有返回值均爲NULL。下面是測試：相同的Dataframes斷言不等 - Python熊貓

def test_get_data(self): 

    ### SET UP 

    self.report._query = "SELECT * FROM floor LIMIT 3"; 
    self.report._columns = ['id', 'facility_id', 'name', 'created', 'modified', 'external_id'] 
    self.d = {'id': p.Series([1, 2, 3]), 
       'facility_id': p.Series([1, 1, 1]), 
       'name': p.Series(['1st Floor', '2nd Floor', '3rd Floor']), 
       'created': p.Series(['None', 'None', 'None']), 
       'modified': p.Series([datetime.strptime('2012-10-06 01:08:27', '%Y-%m-%d %H:%M:%S'), 
            datetime.strptime('2012-10-06 01:08:27', '%Y-%m-%d %H:%M:%S'), 
            datetime.strptime('2012-10-06 01:08:27', '%Y-%m-%d %H:%M:%S')]), 
       'external_id': p.Series(['None', 'None', 'None']) 
       } 
    self.df = p.DataFrame(data=self.d, columns=['id', 'facility_id', 'name', 'created', 'modified', 'external_id']) 
    self.df.fillna('None') 
    print(self.df) 
    ### CODE UNDER TEST 

    result = self.report.get_data(self.report._cursor_web) 
    print(result) 
    ### ASSERTIONS 

    assert_frame_equal(result, self.df)

這裏是控制檯輸出（注意在測試代碼的打印語句的手動構造數據幀是在上面，從被測試的函數導出的一個在底部。）：

. id facility_id  name created   modified external_id 
0 1   1 1st Floor None 2012-10-06 01:08:27  None 
1 2   1 2nd Floor None 2012-10-06 01:08:27  None 
2 3   1 3rd Floor None 2012-10-06 01:08:27  None 
    id facility_id  name created   modified external_id 
0 1   1 1st Floor None 2012-10-06 01:08:27  None 
1 2   1 2nd Floor None 2012-10-06 01:08:27  None 
2 3   1 3rd Floor None 2012-10-06 01:08:27  None 
F 
====================================================================== 
FAIL: test_get_data (__main__.ReportTestCase) 
---------------------------------------------------------------------- 
Traceback (most recent call last): 
    File "/path/to/file/ReportsTestCase.py", line 46, in test_get_data 
    assert_frame_equal(result, self.df) 
    File "/usr/local/lib/python2.7/site-packages/pandas/util/testing.py", line 1313, in assert_frame_equal 
obj='DataFrame.iloc[:, {0}]'.format(i)) 
    File "/usr/local/lib/python2.7/site-packages/pandas/util/testing.py", line 1181, in assert_series_equal 
obj='{0}'.format(obj)) 
    File "pandas/src/testing.pyx", line 59, in pandas._testing.assert_almost_equal (pandas/src/testing.c:4156) 
    File "pandas/src/testing.pyx", line 173, in pandas._testing.assert_almost_equal (pandas/src/testing.c:3274) 
    File "/usr/local/lib/python2.7/site-packages/pandas/util/testing.py", line 1018, in raise_assert_detail 
raise AssertionError(msg)

Asse田：DataFrame.iloc [:, 3]是不同的

DataFrame.iloc[:, 3] values are different (100.0 %) 
[left]: [None, None, None] 
[right]: [None, None, None] 

---------------------------------------------------------------------- 
Ran 1 test in 0.354s 

FAILED (failures=1)

我估計「創造」，列包含在左側和右側都逸「無」的三個字符串值aframes。爲什麼它斷言不平等？

來源

2017-06-06 OnlyDean

也許其中一個不是字符串「None」，而是NoneType ['None']（https://docs.python.org/3/library/constants.html）？ – ayhan

@ayhan就是這樣，謝謝！我還沒有遇到NoneType。請將您的答案作爲答案發布，我會接受它！ – OnlyDean

Python也有一個內置常量None，它與字符串'None'不同。從docs：

None

The sole value of the type NoneType. None is frequently used to represent the absence of a value, as when default arguments are not passed to a function. Assignments to None are illegal and raise a SyntaxError.

在比較None對'None'（None == 'None'）的情況下，結果會是假的。因此，如果其中一個DataFrame包含None，而另一個包含'None'，則assert_frame_equal將引發AssertionError。

來源

2017-06-06 20:34:36 ayhan

相同的Dataframes斷言不等 - Python熊貓

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