“Making a list, checking it twice……cause man these are confusing”: ‘twas the night before list comprehensions....
Tags: beginners, python, newbie, listcomprehensions
Published: 2023-07-26 14:20:17

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!

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/4y5b7l1jabbzym6ymbbo.gif)


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!

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/c4o3ky5c5t34jk3x3mx3.png)



## 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!


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/sumcvbs8n9dsyq5i0r3y.gif)


Happy coding!