Develop Reference

Python + Linux - Excel to HTML (keeping format)

I'm looking for a way to convert excel to html while preserving formatting.
I know this is doable on windows due to the availability of some underlying win32 libraries, (eg via xlwings
Python - Excel to HTML (keeping format))
But I'm looking for a solution on Linux.
I've also come by Aspose Cells but this requires a paid license or else it will add a lot of extra junk to the output that needs to be scrubbed out.
And lastly I tried the python lib xlsx2html but it does a very poor job at preserving formatting.
Are there any suggestions for a Linux based solution? I'd also be interested in tools written in other languages that can be easily wrapped around via python.
Thanks in advance!
Update:
Here is an example of a random excel sheet I converted via excel itself that I would like to reproduce. It has some colors, some border variations, some merged cells and some font sizes to see if they all work.

You can use LibreOffice to convert an Excel file to a HTML file using the command line:
# --convert-to implies --headless so it's not mandatory to specify --headless
soffice --headless --convert-to html data.xlsx
You can refer to the documentation to know more about other CLI parameters.

I think you should search for Excel to HTML in the JS world not python (I am not saying it is not possible, but It's more usual in JS), I promise you will get better results.
In my opinion, finding a JS-based solution and make a python wrapper can be more helpful. Because in JS community, they struggled more than another communities to import and work with Excels.
Another idea is to change your approach, look for how you can import an Excel file in an embedded way or iframe inside an HTML page with JS and then export it.
But again, I highly recommend to check JS libraries or GitHub repositories, some of them care about formatting.

Data storage for standalone python application

I want to make a python program (with a PyQt GUI, but I don't know whether that is relevant) that has to save some information that I want to store even when the program closes. Example for information I want to store:
The user can search for a file in a file dialog window. I want to start the file dialog window in the previously used directory, even if the program is closed in between file searches.
The user can enter their own categories to sort items, building up on some of my predefined categories. These new categories should be available the next time the program starts.
Now I'm wondering what the proper way to store such information is. Should I use pickle? A proper database (I know a tiny bit of sqlite3, but would have to read up on that)? A simple text file that I parse myself? One thing for data like in example 1., another for data like in example 2.?
Also, whatever way to store it I use, where would I put that file?
I'm asking in the context that I might want to later make my program available to others as a standalone application (using py2app, py2exe or PyInstaller).
Right now I'm just saving a pickle file in the directory that my .py file is in, like this answer reconmends, but the answer also specifically mentions:
for a personal project it might be enough.
(emphasis mine)
Is using pickle also the "proper, professional" way, if I want to make the program available to other people as a standalone application?

Choice depends on your approach to data you store, which is yours?:
user should be able to alter it without usage of my program
user should be prevented from altering it with program other than my program
If first you might consider deploying JSON open-standard file format, for which Python has ready library called json. In effect you get text (which you can save to file) which is human-readable and can be edited in text editor. Also there exist JSON file viewers and editors which made viewing/editing of JSON files easier.

I think SQLite3 is the better solution in this case as Moldovan commented.
There is a problem in pickle, sometimes pickling format can be change across python versions and there are greater advantages of using sqlite3.

Write data to excel template

I need to create some excel tables, but these tables don't have simple look.
There are some pictures, some special fonts etc.
But the complicated parts are static, that means always the same.
So my idea was, I will create an excel-template with these tricky parts and then from python just insert dynamic data to this template.
I am working with pandas framework, but I didn't find a way how to do that with or without this framework.
Any idea?

There isn't an easy way to do this with any of the usual "direct file manipulation" libraries in Python (xlrd, xlwt, XlsxWriter, OpenPyXL; these are what pandas uses). The reason is that the structure of a workbook file is such that it's impossible or prohibitively difficult (depending on whether you're talking about .xls or .xlsx) to do anything resembling "in-place" editing, short of re-implementing Excel itself.
So for what you're trying to do, your best option is to let Excel do the work. (I'm assuming you can run Excel, since you mention that you'd like to create Excel templates.) There are ways to automate Excel, the most straightforward probably being Microsoft's VBA or VBScript. But if you want to do it in Python, you can, using PyWin32 or pywinauto.

Editing excel spreadsheets with python

I'll start off by saying that I'm new to python. I'm trying to create an application that is a simple Q+A and will export the answers to specific cells of an excel. I have an existing spreadsheet that i would like to modify and save as a separate outfile leaving the original untouched. I've seen various ways that i can append the file but will overwrite the original.
As an example, i would like this code;
hq = input('Headquarters: ')
to put the response in cell S1
Am I way off base trying to use Python for this task? Any Help would be greatly appreciated!
-Paul

There may not be very straightforward solutions but there are a couple of tools which might help you.
The first one is openpyxl: https://openpyxl.readthedocs.org/en/2.0.2/# If you have xlsx files, you should be able to modify them with this.
You might also be able to do what you want to do by using xlutils module: http://pythonhosted.org/xlutils/index.html However, then you'll need to first read the file, then edit it, and then save it to another file. Formatting may be lost, etc.
This is heavily YMMV due to the not-so-well defined file format, but I'd start with openpyxl.

Generating correct excel xls format

I created a little script in python to generate an excel compatible xml file (saved with xls extension). The file is generated from a part database so I can place an order with the extracted data.
On the website for ordering the parts, you can import the excel file so the order fills automatically. The problem here is that each time I want to make an order, I have to open excel and save the file with xls extension of type MS Excel 97-2003 to get the import working.
The excel document then looks exactly the same, but when opened with notepad, we cannot see the xml anymore, only binary dump.
Is there a way to automate this process, by running a bat file or maybe adding some line to my python script so it is converted in the proper format?
(I know that question has been asked before, but it never has been answered)

There are two basic approaches to this.
You asked about the first: Automating Excel to open and save the file. There are in fact two ways to do that. The second is to use Python tools that can create the file directly in Python without Excel's help. So:
1a: Automating Excel through its automation interface.
Excel is designed to be controlled by external apps, through COM automation. Python has a great COM-automation interface inside of pywin32. Unfortunately, the documentation on pywin32 is not that great, and all of the documentation on Excel's COM automation interface is written for JScript, VB, .NET, or raw COM in C. Fortunately, there are a number of questions on this site about using win32com to drive Excel, such as this one, so you can probably figure it out yourself. It would look something like this:
import win32com.client
excel = win32com.client.Dispatch('Excel.Application')
spreadsheet = excel.Workbooks.Open('C:/path/to/spreadsheet.xml')
spreadsheet.SaveAs('C:/path/to/spreadsheet.xls', fileformat=excel.xlExcel8)
That isn't tested in any way, because I don't have a Windows box with Excel handy. And I vaguely remember having problems getting access to the fileformat names from win32com and just punting and looking up the equivalent numbers (a quick google for "fileformat xlExcel8" shows that the numerical equivalent is 56, and confirms that's the right format for 97-2003 binary xls).
Of course if you don't need to do it in Python, MSDN is full of great examples in JScript, VBA, etc.
The documentation you need is all on MSDN (since the Office Developer Network for Excel was merged into MSDN, and then apparently became a 404 page). The top-level page for Excel is Welcome to the Excel 2013 developer reference (if you want a different version, click on "Office client development" in the navigation thingy above and pick a different version), and what you mostly care about is the Object model reference. You can also find the same documentation (often links to the exact same webpages) in Excel's built-in help. For example, that's where you find out that the Application object has a Workbooks property, which is a Workbooks object, which has Open and Add methods that return a Workbook object, which has a SaveAs method, which takes an optional FileFormat parameter of type XlFileFormat, which has a value xlExcel8 = 56.
As I implied earlier, you may not be able to access enumeration values like xlExcel8 for some reason which I no longer remember, but you can look the value up on MSDN (or just Google it) and put the number 56 instead.
The other documentation (both here and elsewhere within MSDN) is usually either stuff you can guess yourself, or stuff that isn't relevant from win32com. Unfortunately, the already-sparse win32com documentation expects you to have read that documentation—but fortunately, the examples are enough to muddle your way through almost everything but the object model.
1b: Automating Excel via its GUI.
Automating a GUI on Windows is a huge pain, but there are a number of tools that make it a whole lot easier, such as pywinauto. You may be able to just use swapy to write the pywinauto script for you.
If you don't need to do it in Python, separate scripting systems like AutoIt have an even larger user base and even more examples to make your life easier.
2: Doing it all in Python.
xlutils, part of python-excel, may be able to do what you want, without touching Excel at all.