“Making a list, checking it twice……cause man these are confusing”: ‘twas the night before list comprehensions....
Jessica Papa
Posted on July 26, 2023
So, the day before my code challenge do-over, I was having a hard time wrapping my head around Python and object relationships. I was really hoping for that magical moment when it would all just click. During our practice challenge, I totally thought I blew it, but then when we went over it, something just clicked in my brain and suddenly I got it!
So, I had this moment where everything just made sense, but honestly, I'm still struggling with this issue. But, I figured writing about it would not only help me, but maybe others going through the same thing too. Life can be a crazy ride, am I right?
Let's dig a little deeper into this topic!
Of course, we know our comfy friend the for loop
, it's safe and easier to understand when you're first learning Python!
Example:
the_list = []
for concert in Concert.all:
if concert.venue == self:
the_list.append( concert )
return the_list
Code breakdown:
the_list = []
: This creates an empty list called the_list
that will be used to store the concerts related with the venue.
for concert in Concert.all
: Concert.all
is a list (or iterable) that has all available concerts. The loop iterates through each concert in this list.
if concert.venue == self
: This line checks if the venue of the current concert matches the given self
, where self
is referring to the venue object within the context of a method or class.
the_list.append(concert)
: If the venue matches, the concert is appended to the the_list
.
After the loop is completed, the function returns the_list
, which contains all the concerts associated with the given venue.
Yay, for loops!
So, have you ever heard of list comprehensions? They're actually a really handy tool in Python that can make your code a lot more efficient when working with lists.
Basically, you can use them to create a new list by applying an expression to each item in an existing list (or other iterable). This makes your code shorter and easier to read - pretty cool, right?
Example:
return [c for c in Concert.all if c.venue == self]
Code breakdown:
return
: This indicates that the function will return a list.
c for c in Concert.all:
This is the list comprehension syntax. The first c
represents the whole concert instance that will go in your new list. The second c
iterates through each c
(concert) in Concert.all
, which contains all available concerts.
if c.venue == self
: The list comprehension includes c
in the result only if the venue attribute of the c
(concert) matches the value of self
.
self
is referring to the venue object within the context of a method or class, representing the current venue.
I gotta give a shoutout to my teacher Adam for helping me have that "a-ha" moment cause this breakdown really helped me understand!
Remember:
When that imposter syndrome hits, think back on how far you have come!
Did you know what you know now a week ago?!
YOU CAN AND YOU ARE DOING THIS! BE KIND TO YOURSELF!
Happy coding!
Posted on July 26, 2023
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