Writing to XML files in Excel 2010 corrupts files - python

The project I'm working on requires that I programmatically change a .xlsx file to a .zip file, extract all of the files, then make alterations to the underlying XML that makes up an excel spreadsheet. However, I've found that whenever I attempt to write to the file that requires changes, the spreadsheet becomes corrupted once I re-zip the files and changes the extension back to .xlsx. I should note that if I manually change values within the xml files (for example, changing the name of "sheet1" to "test", there are no problems, but I need to do this using python if possible, so that isn't an option.
Does excel have some sort of checksum/integrity verifier that causes corruption when significant changes are made? If so, what does it look for and is there a way to get around it?
I'm using Windows 7 - 64 bit.

Related

openpyxl corrupts spreadsheet if it contains a data source

I use openpyxl to interact with Excel files using Python 3.7. I open and save my .xlsx spreadsheets as follows:
from openpyxl import load_workbook
wb.load_workbook('file.xlsx', read_only=False)
wb.save('file.xlsx')
If file.xlsx contains no links to external data sources (such as SQL Server or Postgre-SQL), then there is no problem with the saved file and it opens okay in Excel after being processed by my Python script.
However, if file.xlsx does contain a link to external data, then upon executing the above script, the output file is now corrupted. When opening the file in Excel, the following error is reported and I have the option of attempting to recover it. When recovering, the data remains but all links to the data source are gone.
> We found a problem with some content in file.xlsx. Do you want us to try to recover as much as we can? If you trust the source of this workbook, click Yes.
It is easy to reproduce this error as follows:
Create a blank spreadsheet and save it as file.xlsx.
Run the above three lines of Python code to open and save the file. You will see this works fine and has no impact on the spreadsheet.
Now open file.xlsx in Excel and, from the Data tab, choose a data source. You can choose any data source (link to a csv file, a table within Excel, or an external data source - it doesn't matter).
Save the spreadsheet, then run the above Python script (which again, simply opens and saves it).
Open file.xlsx in Excel. You will see that it is now corrupted.
My conclusion is that, at the moment, openpyxl doesn't support spreadsheets that contain links to external data. It would be useful to have this confirmed, or for a workaround to the above issue to be proposed.
Thanks!!

How can I update workbook links when using pd.read_excel()?

The question is pretty simple, actually.
I'm reading an Excel file using Pandas. When I open it using Office's Excel in my Desktop I'm prompted to Enable Content and then Update Links [that is, update values in those cells importing information from cells in other workbooks and xslx files], so it reads other files in some other folders.
While using pd.read_excel('filename') however that option is not available, and I'm afraid it's importing the data previously contained in the spreadsheet without updating it. Is there a workaround?

Embed CSV in Excel and import the data

I wrote a tool that extracts data from a large DB and outputs it to an Excel file along with (conditional) formatting to improve readability. For this I use Python with openpyxl on a Linux machine. It works great, but this package is rather slow for writing Excel.
It seems to be a lot quicker to dump the table as (compressed) csv, import that into Excel and apply formatting there using a macro/vba.
To automate the process I'd like to create an empty Excel file pre-loaded with the required VBA to do the formatting; a template. For every data dump, the data is embedded (compressed using deflate) into the Excel file and loaded into the Workbook upon opening the document (or using a "LOAD" button to circumvent macro related security things).
However, just adding some file into the Excel file raises an error when opened:
We found a problem with some content in 'Werkmap1_test_embed.xlsx'. Do you want us to try to recover as much as we can? If you trust the source of this workbook, click Yes.
Clicking Yes opens the file and shows some tracing information as XML:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<recoveryLog xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
<logFileName>Repair Result to Werkmap1_OLE_Word0.xml</logFileName>
<summary>Errors were detected in file '/Users/joostk/mnt/cluster/Werkmap1_OLE_Word.xlsx'</summary>
<additionalInfo>
<info>Excel completed file level validation and repair. Some parts of this workbook may have been repaired or discarded.</info>
</additionalInfo>
</recoveryLog>
Is it possible to avoid this? How would I embed a file into the Excel ZIP? Do I need to update some file table (which I could not file easily).
When that's done, I'd like to import the data. Can I access files in the Excel ZIP from VBA? I guess not, and I need to extract the data to some temporary path and load it from there.
I have found these helpful answers elsewhere to load ZIP and plain text:
https://stackoverflow.com/a/35781621/4998990
https://stackoverflow.com/a/11267603/4998990
Many thanks for sharing your thoughts!
so my "Answer" here is that this is caused by using Named Ranges, or an underlying table, or an embedded Query/Connection. When you start manipulating this file you will get the error that you are talking about:
There is no harm to the file if you click "yes" and open. Excel will open this in Repaired Mode which will require you to re-save the file.
The way I've worked around this is to re-read the "repaired" file, in python, and save it as another file or replace it. Essentially just do an extra step of re-reading the data into memory, and write it to a new file. The error will go away. As always, test this method before deploying to production to ensure no records are lost. The way I solve it is with two lines of pandas.
import pandas as pd
repair = pd.read_excel('PATH_TO_REPAIR_FILE')
new_file = repair.to_excel('PATH_TO_WHERE_NEW_FILE_GOES')

Error opening text file saved with .xls extension in python

I'm using labview to create and save data from an experiment. Labview itself creates a text file but saves it automatically with a .xls extension (word 1997-2003--it's an old setup that was never changed because it never broke). Whenever I go to open one of the data files, excel spits out this:
"The file you are trying to open, 'name.ext', is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted source before opening the file. Do you want to open the file now?"
I'm generating a lot of data, so I want to use python to sort it out and do some quick analysis over files in a directory.
The problem is that python doesn't like that it's a text file saved with a .xls extension. It can cycle through the directory just fine to get the file names, but whenver I actually try to open the file or do anything with it, I get the error in the image attached. This happens if I change the extension to .xls, .xlsx, or do nothing with it at all and let it try to open the original filename.
error message
I literally have hundreds of these .xls files. I know I can go through, open each one in excel and save as a real excel file by hand, but that will take hours. Can someone please help me figure a way around this error in python?
Dropbox Data File set
*Update. Matlab, when trying to read one of the files using xlsread, says this:
Error using xlsread (line 251)
File C:\Users\zane\Documents\Research Projects\PneuFish Project\Data\Nov 28 2016 ATI
Data\ATI_Data_2016Y_11M_28D_16h_36m_01s.xls not in Microsoft Excel Format.
Thank you!
You can use the module xlrd.
import xlrd
import csv
def csv_from_excel():
wb = xlrd.open_workbook('your_workbook.xls')
sh = wb.sheet_by_name('Sheet1')
your_csv_file = open('your_csv_file.csv', 'wb')
wr = csv.writer(your_csv_file, quoting=csv.QUOTE_ALL)
for rownum in xrange(sh.nrows):
wr.writerow(sh.row_values(rownum))
your_csv_file.close()
Taken from This Post
This will convert from .xls to .csv, which is easily manipulated with Python.
You've said that the file is a text file, so don't tell Python that it's an Excel file. Just use Python's open and read it as text, then do whatever you want with it. open doesn't care what extension a file has.
I'm going to guess that the format is actually tab-delimited. From memory, earlier versions of Excel would read in tab-delimited text files with the .xls extension without complaint, whereas csv files would always bring up the text import wizard, so this was a common dodge if saving data intended for Excel from a program that didn't support writing real Excel files.
If you want the LabVIEW code to write real Excel files in future, the Write to Measurement File express VI has an option to write in xlsx format. I'm not sure which version of LabVIEW first introduced this but it's been there for a few years now.

Adding data validation/macro to existing xls file using python on linux

I have a bunch of xls files to which i need to add a data validation (comboboxes) for some cells using python. I am working on linux.
Alternatively, the same could be achieved by adding a macro to a Worksheet that will run upon the file opening and insert data validation.
Most libraries I found were either for Windows or were not able to do that/edit existing file.
Any ideas what is the best (or at least possible) way to achieve that?

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