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I am trying to access some of the columns in a Microsoft Access database table which contains numbers of type double but I am getting the error mentioned in the title.The code used for querying the database is as below, the error is occurring in the line where cur.execute(....) command is executed. Basically I am trying filter out data captured in a particular time interval. If I exclude the columns CM3_Up, CG3_Up, CM3_Down, CG3_Down which contains double data type in the cur.execute(....) command I wont get the error. Same logic was used to access double data type from other tables and it worked fine, I am not sure what is going wrong.

Code:

start =datetime.datetime(2015,03,28,00,00) a=start b=start+datetime.timedelta(0,240) r=7 while a < (start+datetime.timedelta(1)): params = (a,b) sql = "SELECT Date_Time, CM3_Up, CG3_Up, CM3_Down, CG3_Down FROM Lysimeter_Facility_Data_5 WHERE Date_Time >= ? AND Date_Time <= ?" for row in cur.execute(sql,params): if row is None: continue r = r+1 ws.cell(row = r,column=12).value = row.get('CM3_Up') ws.cell(row = r,column=13).value = row.get('CG3_Up') ws.cell(row = r,column=14).value = row.get('CM3_Down') ws.cell(row = r,column=15).value = row.get('CG3_Down') a = a+five_min b = b+five_min wb.save('..\SE_SW_Lysimeters_Weather_Mass_Experiment-02_03_26_2015.xlsx')

Complete error report:

Traceback (most recent call last): File "C:\DB_PY\access_mdb\db_to_xl.py", line 318, in <module> for row in cur.execute(sql,params): File "build\bdist.win32\egg\pypyodbc.py", line 1920, in next row = self.fetchone() File "build\bdist.win32\egg\pypyodbc.py", line 1871, in fetchone value_list.append(buf_cvt_func(alloc_buffer.value)) ValueError: could not convert string to float: E-3
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2 Answers 2

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As to this discussion: Python: trouble reading number format

the trouble could be that e should be d, like:

float(row.get('CM3_Up').replace('E', 'D'))

Sounds weird to me though, but I know only little of Python.

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2 Comments

This solution didn't work
Then I'm out of ideas, sorry.
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It sounds like you receive strings like '2.34E-3', so try with a conversion. Don't know Python, but in C# it could be like:

ws.cell(row = r,column=12).value = Convert.ToDouble(row.get('CM3_Up')) ws.cell(row = r,column=13).value = Convert.ToDouble(row.get('CG3_Up')) ws.cell(row = r,column=14).value = Convert.ToDouble(row.get('CM3_Down')) ws.cell(row = r,column=15).value = Convert.ToDouble(row.get('CG3_Down'))
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In Python it would be float(row.get('CM3_Up')).
I tried float(row.get('CM3_Up')) but the same error is displayed. Just to add some more detail, the values that are read from the access database are like: -2.91953029510136(CM3_Up), -84.8983788757143 (CG3_Up) , 3.04633983884509 (CM3_Down),-5.80184926507136(CG3_Down ).
@Mukunda - Can you provide a small sample database with the table that causes the error? If so, please upload it to an Internet-accessible location (something like Wikisend) and post the link here so we can try to recreate the issue.
Please find the link for the sample database here, wikisend.com/download/504484/mukunda_sample.accdb
That table is perfectly well.
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