🐍🚀 What else does else do?
Hey there, 👋
How is your Python going?
In this Mathspp Insider 🐍🚀 email we’ll talk about
else statements in
for loops and I’ll also share some exciting news I have!
else statement in a
Everyone knows the
else statement from conditional blocks.
if some_condition: if you want to run some code only in case
some_condition is true and then the
else: block is used if you want to run code in case it wasn’t.
else is much more than that.
Apparently, you can also use
else after a
Let me tell you what it does…
But first, some news:
The Python Problem-Solving Bootcamp is back!
The Python Problem-Solving Bootcamp is a 21-day intensive bootcamp where we get together to solve 42 programming challenges in Python.
This will be the second edition of this bootcamp, after the first one was so successful!
(21 ⭐️⭐️⭐️⭐️⭐️ reviews and one ⭐️⭐️⭐️⭐️ review!)
The bootcamp will run from the 1st of December up to the 21st.
The bootcamp is fully asynchronous and we’ll have a Discord channel where we’ll discuss ideas and algorithms.
We’ll also have a place to ask for help when we get stuck with a particular problem.
You can read more about the bootcamp here.
You can also reply to this email with questions you might have.
I’ll see you inside 😉
What else does
(Sorry for the bad pun, I couldn’t resist it!)
If you have an
else statement in a
for loop, the
else statement runs only if the loop terminates naturally.
If you use a
break inside the loop, the
else statement does not run.
This can be illustrated with these two excerpts from the REPL:
# No break = we dive into the else >>> for i in range(10): ... pass ... else: ... print("Else!") ... Else!
# Break = we skip the else >>> for i in range(10): ... if i == 5: ... print("Break!") ... break ... else: ... print("Else!") ... Break! >>>
This may look weird, and I thought that, too…
So, let that sink in for a second.
You can also take a look at the diagram below; it summarises what I said so far:
Example usage of
else in a
The diagram above summarises really well the point of the
else in a
It really only makes sense in loops that contain a
You are creating an application and there are a couple of places where the user may save their configuration files.
You use the loop to look for the configuration file.
If you find the file, you can open it and parse the configuration.
break the loop.
However, if you cannot find any configuration file, you never hit the
break, and you enter the
else statement can be used to
raise an error; or
create a default configuration; or
prompt the user to create their configuration at that point in time; or
whatever you want!
So, this is an example of where the
else could make sense.
Did this example make sense to you?
If not, reply to this email and I’ll help you out!
Now, here’s a small challenge for you:
Try to think of a situation where the
else might be useful.
It can be a situation where you used it in the past or a situation where you think it could be useful.
Reply to this email and share your example with me!
In case you want to practise solving some programming challenges in Python, check out the Python Problem-Solving Bootcamp.
The next cohort starts on the 1st of December and we’ll be solving 42 challenges in 21 days.
It’s going to be A LOT of fun.
Sign up here: https://mathspp.com/pythonbootcamp.
In Case You Missed It, I’ve been hard at work these past few days!
I published a Python package called
error-links. You install it with
pip install error-linksand then you run the command
What does it do?
It shows Google and Python docs links whenever your code breaks with an exception.
This is the GitHub repo: https://github.com/rodrigogiraoserrao/error-links/
I’ve also published the first few articles of my series “Building a Python Compiler and Interpreter” on my blog. You can read them here: https://mathspp.com/blog/tag:bpci
🐍🚀 How was this email?