SQL: Get the count of related records
Micro tutorial: SQL select the count of related records and sort by it.
Posts by Category
Databases
FileMaker
Working with FileMaker data in Python
This is an old post. You may also be interested in accessing your FileMaker database via the new Data API. I wrote a Python wrapper to make it easier: python...
Mathematics
The basics of Logarithms – with examples
Logarithms are widely used in computer science (e.g. for algorithm analyses, floating point number limitations, scaling data, feature transformations). Not c...
LaTeX mathematics cheat sheet
LaTeX is the de facto standard typesetting system for scientific writing. Find a a cheat sheet with the most frequent used mathematics commands here.
Micro Tutorial
Load password protected Excel files into Pandas DataFrame
When trying to read an Excel file into a Pandas DataFrame gives you the following error, the issue might be that you are dealing with a password protected Ex...
Using vi commands in your bash shell
Entering a long shell command and then moving the cursor around to correct parts of it always felt a bit clunky to me. I remembered some of the <ctrl>/...
Count elementwise matches for two NumPy arrays
Let’s say we have two integer NumPy arrays and want to count the number of elementwise matches.
SQL: Get the count of related records
Micro tutorial: SQL select the count of related records and sort by it.
Pandas: Select rows that match a string
Micro tutorial: select rows of a Pandas DataFrame that match a (partial) string.
Miscellaneous
A few updates
After having neglected my blog over the last few months, I want to start posting more frequently again (New Year’s resolutions and all that).
LaTeX mathematics cheat sheet
LaTeX is the de facto standard typesetting system for scientific writing. Find a a cheat sheet with the most frequent used mathematics commands here.
Python
Using launchd agents to schedule scripts on macOS
Even though launchd has been around for quite some time now, I was still using crontab for scheduling some of my scripts until recently. Since launchd Launch...
Load password protected Excel files into Pandas DataFrame
When trying to read an Excel file into a Pandas DataFrame gives you the following error, the issue might be that you are dealing with a password protected Ex...
Bokeh plots with Flask and AJAX
Tutorial on creating Bokeh plots with an AJAX data source, served from an existing Flask app.
The basics of Logarithms – with examples
Logarithms are widely used in computer science (e.g. for algorithm analyses, floating point number limitations, scaling data, feature transformations). Not c...
Count elementwise matches for two NumPy arrays
Let’s say we have two integer NumPy arrays and want to count the number of elementwise matches.
Running Flask on macOS with mod_wsgi/wsgi-express
Tutorial on setting up your Flask application to run on macOS with WSGI
Pandas: Select rows that match a string
Micro tutorial: select rows of a Pandas DataFrame that match a (partial) string.
Comparing two Excel columns with Pandas and Numpy
Having been asked multiple times if I can quickly compare two numeric columns from an excel file, I set up a small Jupyter notebook (and an R script) to show...
Display inline images in a Jupyter notebook with Matplotlib
Today I was working with the MNIST handwritten digits data and wanted to display a few images in a Jupyter notebook. After looking at PIL, then Pillow, I fou...
Debugging Jupyter notebooks
While searching for ways to debug code in a Jupyter notebook, I found a lot of outdated posts. So I decided to quickly write up my findings.
Resolving import issues when deploying Python code to AWS Lambda
AWS Lambda is Amazon’s “serverless” compute platform that basically lets you run code without thinking (too much) of servers. I used Lambda in the past, thou...
Indexing: A few handy ways to access NumPy arrays
The following code snippets should serve as an (incomplete) cheat sheet for accessing NumPy arrays. All examples expect an import numpy as np.
Working with FileMaker data in Python
This is an old post. You may also be interested in accessing your FileMaker database via the new Data API. I wrote a Python wrapper to make it easier: python...
R Stats
Comparing two Excel columns with Pandas and Numpy
Having been asked multiple times if I can quickly compare two numeric columns from an excel file, I set up a small Jupyter notebook (and an R script) to show...
Systems
Using launchd agents to schedule scripts on macOS
Even though launchd has been around for quite some time now, I was still using crontab for scheduling some of my scripts until recently. Since launchd Launch...
Using vi commands in your bash shell
Entering a long shell command and then moving the cursor around to correct parts of it always felt a bit clunky to me. I remembered some of the <ctrl>/...
Basic understanding of IPv4 addresses
In a recent project I needed to anonymize IP addresses in tracking data. While masking a few bits from an IP address is not so interesting, it’s a good excus...
VPN: Temporarily solve same subnet conflicts
I recently had the problem of needing to establish a connection to a server behind a VPN that was in the same subnet as the network I was connecting from. Ev...
Running Flask on macOS with mod_wsgi/wsgi-express
Tutorial on setting up your Flask application to run on macOS with WSGI
Sharing a VPN connection with another device on macOS Sierra/El Capitan
There are multiple reasons why you would want to share a VPN connection from your Mac with another device. Maybe you have to install a proprietary VPN client...