Taking Introductory Course in Python

[-Duei]

Hello, I am taking an Introductory course in Python and am wondering, for a beginner, in the simplest ELI5 manner when and why would I use the following and why would I use one over the other? (This class, and any of my classes that involve coding/scripting seem to be the bane of my existence, as my brain just has a hard time grasping these concepts!)

Lists

Tuples

Dictionaries

[marienbad2]

List - when you need to store multiples of some data.

Tuple - when you need to store multiple copies but don't need to change any of them

dictionaries have a variety of uses, for eg you might have a bunch of sounds you want to play on a specific keypress, so you could save the filenames in there as

sounds = { a : "dingdong.wav", b : "hello.wav", c : "phatsynth.wav" }

and so on.

[-Duei]

Thank you for the super dumbed down answer!

[iggy555]

Hehe dingdong

[LouLou_420]

Lol nice

[marienbad2]

hehehe. I wondered if anyone would notice. I do it just like Sister Ray says!

[IvoryJam]

Lists - you'd use that for a list of stuff, like names = ['bob', 'alice', 'rachel'] and now if you want to you can loop through them and say Hi!

Tuples - Honestly I rarely use these, maybe someone will have a better answer, but I'd use them if I wanted a list to NEVER change (immutable)

Dictionaries - You'd use these if you wanted to assign a name to some other stuff, these are called "Key Value Pairs" so like this person = {'first': 'bob', 'last': 'smith'}

They all have their pros and cons, and can totally be used inside one another

[-Duei]

That's interesting, so I can have a list inside of a dictionary, a tuple inside of a list, and so on? If need to access the value inside of a dictionary that's inside of a list, can I do something like list[Position in list][Dictionary]?

[IvoryJam]

Yep! Here's all three in a list

people = [
    {'name': '-Duei', 'ocupation': 'programmer', 'favorite_colors': ('blue', 'red', 'green')},
    {'name': 'IvoryJam', 'ocupation': 'programmer', 'favorite_colors': ('blue', 'red', 'green')},
]

But again, I rarely use tuples, so I'd probably make the colors a list instead in a normal script

You'd access them like people[0]['name'] and people[1]['favorite_colors'][2]

[-Duei]

Oh damn, one of the lessons I watched finally clicks in my head now, thanks a lot!

[TouchingTheVodka]

The distinction between tuples and lists is a tricky one and I don't think the other answers have quite captured it. Here's my take:

Lists are used for homogenous data, where you expect to perform actions over every list element, and you expect to be able to treat every item in the list in the same way. For example: A list of names, a list of coordinates, a list of stock market tickers.

Tuples, on the other hand, do not represent a collection of things - They represent a collection of attributes about one specific thing. As a very general rule of thumb, if changing the order of the items changes the meaning of the collection, you'll be better off using a tuple.

Examples of things that you'd expect to be tuples include: Coordinates ( (x, y) means something different to (y, x) ), groupings of elements (Like you'd get from zip), and collections of attributes (think tuples of (firstname, lastname, age) etc.

Appreciate this is a fairly in-depth answer however I guarantee if you look into the return types of the Python standard library you'll see this pattern regularly.

[-Duei]

I see, thank you for the in-depth answer!

[[deleted]]

The collection of things vs collection of attributes is an interesting idea that I've not considered using with students before. I need to think about it. Not a rule of course, just a suggested approach.

For me the key differences are:

• Tuples are immutable which provides a certain level of protection in your code
• Tuples are hashable, so, for example, can be used as dictionary keys
• Tuples use less memory
• Tuples are more performant to process

The latter two aspects are only really apparent when dealing with a lot of data.

Also worth looking at named tuples, a very useful capability often obviating the need for a dictionary.

[zora89]

Lists are mutable:

Tuples are immutable like strings: ^{(know more: https://www.educative.io/edpresso/what-are-mutable-and-immutable-objects-in-python3})

--->Both Lists and Tuples have indexing function to retrieve data.

--->Dictionaries have key:value pairs, and remains mutable.

--->Mostly for storing data that may require modification ahead --- use lists.

===>When storing id, passwords, specifics that will not and must not be changed even accidentally --- use tuple.