I am trying to write a python program for appending live stock quotes from a csv file to an excel file (which is already open) using xlrd and xlwt.
The task is summarised below.
From my stock-broker's application, a csv file is continually being updated on my hard disk.
I wish to write a program which, when run, would append the new data from csv file to an excel file, which is kept open (I wonder whether it is possible to read & write an open file).
I wish to keep the file open because I will be having stock-charts in it.
Is it possible? If yes, how?
Not directly. xlutils can use xlrd and xlwt to copy a spreadsheet, and appending to a "to be written" worksheet is straightforward. I don't think reading the open spreadsheet is a problem -- but xlwt will not write to the open book/sheet.
You might write an Excel VBA macro to draw the graphs. In principle, I think a macro from a command workbook could close your stock workbook, invoke your python code to copy and update, open the new spreadsheet, and maybe run the macro to re-draw the graphs.
Another approach is to use matplotlib for the graphs. I'd think a sleep loop could wake up every n seconds, grab the new csv data, append it to your "big" csv data, and re-draw the graph. Taking this approach keeps you in python and should make things a lot easier, imho. Disclosure: my Python is better than my VBA.
Related
We have a rather complicated Excel based VBA Tool that shall be replaced by a proper Database and Python based application step by step.
There will be time of the transition between were the not yet completely ready Python tool and the already existing VBA solution will coexist.
To allow interoperability the Python tool must be able to export the database values into the Excel VBA Tool keeping it intact. Meaning that not only all VBA codes have to work as expected but also Shapes, Special Formats etc, Checkboxes etc. have to work after the export.
Currently a simple:
from openpyxl import load_workbook
wb = load_workbook(r'Tool.xlsm', keep_vba=True)
# Write some data i.e. (not required to destroy the file)
wb["SomeSheet!SomeCell"] = "SomeValue"
wb.save(r"Tool_filled.xlsm")
will destroy the file, i.e. shapes won't work, checkboxes neither. (The resulting file is only 5 MB from originally 8 MB, showing that something went quite wrong).
Is there a way to only modify only the data of an ExcelSheet keeping everything else intact/untouched?
As far I know an Excel Sheet are only zipped .xml files. So it should be possible to edit only the related sheets? Correct?
Is there a more comfortable way as writing everything from scratch to only modify the data of an existing Excel file?
Note: The solution has to work in Linux, so simple remote Excel calls are not an option.
I am writing software that manipulates Excel sheets. So far, I've been using xlrd and xlwt to do so, and everything works pretty well.
It opens a sheet (xlrd) and copies select columns to a new workbook (xlwt)
It then opens the newly created workbook to read data (xlrd) and does some math and formatting with the data (which couldn't be done if the file isn't saved once) - (xlwt saves once again)
However, I am now willing to add charts in my documents, and this function is not supported by xlwt. I have found that xlsxwriter does, but this adds other complications to my code: xlsxwriter only has xlsxwriter.close(), which saves AND closes the document.
Does anyone know if there's any workaround for this? Whenever I use xlsxwriter.close(), my workbook object containing the document I'm writing isn't usable anymore.
Fundamentally, there is no reason you need to read twice and save twice. For your current (no charts) process, you can just read the data you need using xlrd; then do all your processing; and write once with xlwt.
Following this workflow, it is a relatively simple matter to replace xlwt with XlsxWriter.
I have an Excel file(xlsx) that already has lots of data in it. Now I am trying to use Python to write new data into this Excel file. I looked at xlwt, xldd, xlutils, and openpyxl, all of these modules requires you to load the data of my excel sheet, then apply changes and save to a new Excel file. Is there any way to just change the data in the existing excel sheet rather than load workbook or saving to new files?
This is not possible because XLSX files are zip archives and cannot be modified in place. In theory it might be possible to edit only a part of the archive that makes up an OOXML package but, in practice this is almost impossible because relevant data may be spread across different files.
Please check Openpyxl once again. You can load the data, do things with python, write your results in a new sheet in the same file or same sheet and save it (as everything is happening in memory).
e.g:
load data
wb = openpyxl.load_workbook("file.xlsx", data_only=True)
manipulate with python
# python codes
create sheet
some_sheet = wb.create_sheet("someSheet") # by default at the end
program to write in sheet
# program to write in sheet
save file (don't forget to close the excel file if its open before saving, as it will raise "Permission Error")
wb.save("file.xlsx"
here is the link
https://openpyxl.readthedocs.io/en/default/tutorial.html
My problem is rather simple : I have an Excel Sheet that does calculations and creates a graph based on the values of two cells in the sheet. I also have two lists of inputs in text files. I would like to loop through those text files, add the values to the excel sheet, refresh the sheet, and print the resulting graph to a pdf file or an excel file named something like 'input1 - input2.xlsx'.
My programming knowledge is limited, I am decent with Python and have looked into python libraries that work with excel such as openpyxl, however most of those don't seem to work for me for various reasons. Openpyxl deletes the graphs when opening an excel file; XlsxWriter can only write files, not read from them; and xlwings won't work for me.
Should I use python, which I'm familiar with, or would VBA work for this kind of problem? Have any of you ever done something of the sort?
Thanks in advance
As a more transitional approach to what m. wasowski wrote above, I'd suggest you do the following.
Install the pandas package, and see how easy it is to load a file using read_excel. Then, read 10 Minutes to Pandas, and manipulate the data.
You state that the Excel sheet is complex. In general, the more complex it is, this approach will eventually make it simpler. But you don't have to switch everything immediately. You can still do parts in Excel and parts in pandas.
I think you should consider win32Com for excel operation in python instead of Openpyxl,XlsxWriter.
you can read/write excel, create chart and format excel file using win32com without any limitation.
And creating chart you can consider matplotlib, in that after creating chart you can save it in pdf file also.
How do I save an open excel file using python= I currently read the excel workbook using XLRD but I need to save the excel file so any changes the user inputs are read.
I have done this using a VBA script from within excel which saves the workbook every x seconds, but this is not ideal.
How about using xlwt?
for Python 2 -- https://pypi.python.org/pypi/xlwt/0.7.4
for Python 3 -- https://pypi.python.org/pypi/xlwt3/0.1.2
It looks like XLRD is used for reading the data, not interfacing with excel. So no, unless you use a different library using python is not the best way to do this, what is wrong with the VBA script?