🔒 constructors vs literals

[magic bloom]

@south crown

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[tropic skiff]

the constructors allow you to make objects from other objects

!e

print(list("abc"))

[magic bloom]

:white_check_mark: Your 3.13 eval job has completed with return code 0.

['a', 'b', 'c']

[tropic skiff]

tho, the way it works with list and dict is a bit different than with string

string needs the dunder becasue it can so varied the way that you would want to make something into a string

!e

pairs = [
  ("a", 1),
  ("b", 2),
]

print(dict(pairs))

[magic bloom]

:white_check_mark: Your 3.13 eval job has completed with return code 0.

{'a': 1, 'b': 2}

[tropic skiff]

also, empty sets cannot be made without doing set()

because {} means empty dict

do tell me tho, how would you make a list with 1 2 3 in it without using [], and instead using list()?

so there's another difference

list and dict don't use specific dunder methods to their classes

instead, they use other methods

for example, __iter__

which is what makes things such that you can loop through them

the problem with list() is that you need to give it some other value

so like, you could do list([1, 2, 3]), but that's redundant

there is __dict__, but it has a different meaning

yep

yes

there's another way you can use the dict constructor, which is keyword arguments

!e

print(dict(a=1, b=2))

[magic bloom]

:white_check_mark: Your 3.13 eval job has completed with return code 0.

{'a': 1, 'b': 2}

[tropic skiff]

you can also pass a dict-like object to dict, and it will make a new dict out of it

I think it needs .keys() and .__getitem__()

so if you pass a dict to the dict constructor it will make a shallow copy

same with list and list

!e

a = [1, 2, 3]
b = list(a)
print(a is b)

[magic bloom]

:white_check_mark: Your 3.13 eval job has completed with return code 0.

False

[tropic skiff]

yeah

same like doing your_list.copy() in this case

or your_list[:]

check this out

!e

string = "abcbsahbcasjhbvqawugvcasicbash"
print(string)
unique = set(string)
print(unique)
indexable = list(unique)
print(indexable)
indexable[:5] = "hello"
print(indexable)

[magic bloom]

:white_check_mark: Your 3.13 eval job has completed with return code 0.

001 | abcbsahbcasjhbvqawugvcasicbash
002 | {'b', 'h', 'j', 'i', 'v', 'w', 'g', 's', 'q', 'a', 'u', 'c'}
003 | ['b', 'h', 'j', 'i', 'v', 'w', 'g', 's', 'q', 'a', 'u', 'c']
004 | ['h', 'e', 'l', 'l', 'o', 'w', 'g', 's', 'q', 'a', 'u', 'c']

[tropic skiff]

demonstration of using constructors

[magic bloom]

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