The missing piece in my Python scripts

The city's new center boulevard is coming along nicely. It was recently left open for pedestrians, so I took my camera for a morning walk/

My quest to automate parts of my workflows usually involves writing Python scripts to streamline some of my tasks as a Happiness Engineer.

One output has confused me for far longer than it should have, and I was shown the light today (in the form of a pretty simple solution).

My dilemma

Many of my scripts generate template documents. These include meeting agendas, hangout notes, and team reports. These documents include a couple components that I’ve largely automated using Python, such as –

  • Calculating dates and times in reports (sometimes including timezone conversions);
  • Taking inputs I provide in response to command line prompts, running calculations, and adding those to fields in my reports; and so on.

Many of my documents have a static list of team members that I ping much like Twitter mentions when I publish them as posts on internal blogs (we use internal blogs quite a lot, as you can imagine). Those lists each need to be updated manually every time there’s a change in the team composition, in each of the documents the list appears in.

Although the team composition doesn’t change frequently, I often find myself re-using a script for a team report, or hangout agenda, for example, in another group I work with. This means another set of documents where I need to manually create a list of people, and maintain that.

An example could be something like this:

Pinging: @john-doe, @maryjacobs, @davesmith, @janestuart, @tomwright, @steverobinson

The solution

Currently, the first part of generating this sort of list of people is creating a .csv file that looks something like this:


I was planning on using Python Classes to do this, but quickly realised that I don’t understand Classes nearly well enough to using this feature for this aspect of my documents.

I realised that there’s actually a simpler solution using .csv files and the csv module available in Python instead, after watching Corey Schafer‘s tutorial on this, here:

As an aside, Schafer’s tutorials are wonderful!

I was able to borrow from Schafer’s solutions to write a script that produced a list that looks something like this:

Pinging: ['@john-doe', '@maryjacobs', '@davesmith', '@janestuart', '@tomwright', '@steverobinson']

My script looked like this:

import csv

with open('people.csv', 'r') as csv_file:
    csv_reader = csv.DictReader(csv_file)

    members = []

    for line in csv_reader:
        wpuser = f"@{line['wp_user']}"

print(f'Pinging: {members}')

I couldn’t work out how to just generate a list of usernames separated by spaces. I ran into a similar issue with other scripts where I similarly loop over a list of items to produce some sort of list-generated output.

In other words, I couldn’t figure out how to output the list of usernames without the []' characters you see in my initial output.

So, I asked for help on reddit where JohnnyJordaan pointed me to this StackOverflow post that includes a couple solutions to a similar question. I had searched for a solution to my challenge, but didn’t come across this answer (or anything like it).

Clearly, I need to work on my Googling skills when it comes to finding solutions to my coding challenges.

Anyway, the solution that JohnnyJordaan suggested is pretty simple. Instead of using something like print(f'Pinging: {members}'), I could rather join the items in the list with a statement like this:

print(f'Pinging: {", ".join(members)}')

As I suspected, the solution is pretty simple. It just eluded me, completely. So thank you to JohnnyJordaan for the pointer!

I also like the * that came up in one of the StackOverflow solutions, but it doesn’t work with the f strings that I tend to use. Still, there are other ways to use them. Trey Hunner has an interesting post about these operators here (if you’re interested).

By Paul

Enthusiast, writer, Happiness Engineer at Automattic. I take photos too. Passionate about my wife, Gina and #proudDad.

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