Loading dated files in Tableau

Question

I started to use Tableau Desktop as a tool to visualise my data. However, my data is stored in CSV files with a date format name (e.g. datasample_yyyymmdd.csv). I need to be able to load in my files as the date is changing every day. How do I do this in Tableau?

I searched on Google for answers, but nothing clear.

Answer 1

This can be done with Tableau alone if your data is not extremely huge.

1. Create a union in your csv connection, select the type as Wildcard and enter the pattern.

2. Create a data source/extract filter to keep only Top 1 path. (Extract recommended)

3. Final Result (Here 20181111 is the latest file)

PS: For some date formats, TOP 1 of max may not return the correct result. In that case, create a calculated date field from filename and apply TOP1 filter based on that.

Answer 2

This is something that can be done outside of Tableau in a batch command or python script. Both can be automated with Windows scheduler if on Windows. Ultimately, you want to pick up the most recent file and copy it to something like datasample_today.csv then connect Tableau to that file. Tableau will then always be connected to the latest file. Here is how you could do it in Python.

Python:

import glob
import os

list_of_files = glob.glob('/path/to/folder/*.csv') #* is wildcard
latest_file = max(list_of_files, key=os.path.getctime)
print(latest_file)

from shutil import copyfile

copyfile(latest_file, '<your dir>\datasample_today.csv')

I'm not at all proficient in batch commands so you'll have to test this out and there is a lot here on SO to help.

Batch:

FOR /F %%I IN ('DIR *.* /B /O:-D') DO COPY %%I <<NewDir>> & EXIT