in the following codes:
x=list(range(1,11))
print(x)
vs
x = range(1,11)
print(x)
Why do i have to type list first to make this code work? sorry my communcation skills arent so good D:
#🔒 what is this called
tender gust
pure spruceBOT
in the following codes:
x=list(range(1,11))
print(x)
vs
x = range(1,11)
print(x)...
@tender gust
Python help channel opened
thick cape
the vocab you're looking for is "generator" https://wiki.python.org/moin/Generators
tender gust
wont let me click that link
503 Service Unavailable
No server is available to handle this request.
thick cape
oh that's weird
boreal kiln
range returns a range object. not a list.
range object behaves a lot like lists, but aren't lists
tender gust
list is called a generator?
thick cape
err range is just sort of a generator-like object
boreal kiln
the main difference is that range(0, 10000000000000000) works just fine, but using list() on it will allocate a lot of memory
tender gust
I think i know what range is but why do i have to put list infront of it to make it spit out a list of numbers
boreal kiln
because range isn't a list.
a list and a range have different string representations
tender gust
im still kinda lost
thick cape
i suppose a better terminology might be iterable
range is an "iterable" in python
which means it's an object that implements the __next__ method, which can be called with next(foo)
boreal kiln
when you print it, the list generates the characters "[" and the items, separated with "," and ends with a "]" ... a range doesn't do that, because that would mislead what a range is if it prints like a list.
otherwise a range and list behave quite the same.
thick cape
every time you call __next__, you get the next value from the iterator
tender gust
give me one sec to read this 😄
thick cape
tender gust
when you print it, the list generates the characters "[" and the items, separate...
by characters do you mean numbers in x = list(range(1,11))
tender gust
range returns a range object. not a list.
range object behaves a lot like lists,...
what do you mean by range objects sorry im new
thick cape
range returns an iterable, not a list. an iterable is anything that can be looped through. so a list is an iterable, but not all iterables are lists. range can be looped through because it implements a special function called __iter__. python handles this function specially, and makes it work with things like for loops. __iter__ lets range lazily define what values it holds
frank hare
what do you mean by range objects sorry im new
a range is a kind of object just like list or int
slate spoke
range used to return a list in old versions of Python. That wasn't great because range(1_000_000) would create a list with million numbers, taking up a lot of memory
tender gust
im still rereading your guys msg btw
thick cape
the reason you might want something like this, is that it lets you lazily define what values your iterable has. if you're just looping through the range, there's no need to create an entire list of every number in that range, when you only need 1 number at a time. so [0, 1, 2, 3, ... 10000] holds a lot of memory, but range(10000) holds the same amount of memory as range(5) because the values haven't been generated yet
tender gust
@thick cape so list is a genrator?
frank hare
no, a generator is a different type of thing that works a little like a range, but ultimately not relevant here
thick cape
list is an iterable. it can be looped (or "iterated") through
tender gust
would you say list is like a handi cap for range?
frank hare
i wouldnt
thick cape
what do you mean by handicap?
tender gust
without the list function the you cant print the range numbers
boreal kiln
by characters do you mean numbers in x = list(range(1,11))
no, I mean when you print a list, it converts the list into a string representation like "[1, 2, 3]" ... a range simply doesn't do that, because printing a range should give a developer information, that makes it clear it's a range, and not a list.
a range doesn't actually store it's values anywhere. A list does.
frank hare
!e sure you can
for x in range(10):
print(x, end="")
@frank hare :white_check_mark: Your 3.12 eval job has completed with return code 0.
0123456789
there are a lot more things you want to do with lists/ranges than just print them out. the printing can maybe make debugging annoying sometimes, but the core functionality that most people care about is iterating through the values
tender gust
there are a lot more things you want to do with lists/ranges than just print the...
would you say applying list func to the range func is iterating threw the range of the numbers passed into the range func
thick cape
yes, exactly
tender gust
oh shit 😄
thick cape
list(...) works by iterating over the iterable and pushing everything into a list
it's basically ```py
arr = []
for e in iterable:
arr.push(e)
now range is admittedly not a generator, but it's useful sometimes to think of iterables like range as generators
thick cape
for example, you can implement your own range pretty easily
def my_range(start, end):
while start < end:
yield start
start += 1
wet saffron
Well, if you only care about the iterable part of range
and also don't care about the step...
ranges can also be inspected for their start, stop, and step values, and can be indexed (including slicing)
tender gust
it's basically ```py
arr = []
for e in iterable:
arr.push(e)
```
you have me lost in that
frank hare
when you pass an iterable to list, it takes the things from the iterable and puts them in a list
tender gust
when you pass an iterable to `list`, it takes the things from the iterable and p...
range is the iterable in my code?
frank hare
yeah
tender gust
: D
thick cape
yeah so these are equivalent:
arr = []
for i in range(3, 4):
arr.append(i)
arr = list(range(3, 4))
is more or less what i'm trying to say there
wet saffron
the reason that range doesn't show you all the values in its string representation is because that would be against what range is meant to be: lazy
the start, stop and step values can represent all values in the range without showing you all the values. Showing all the values would nullify the laziness of the range (lazy as in not using a bunch of memory to store the values)
thick cape
for example, you can implement your own `range` pretty easily
```py
def my_rang...
for here, yield in python lets you define a function which is a "generator". a generator is a function which is an iterable. you can call it multiple times and get a different value every time. so if you do something like this,
!e ```py
def my_range(start, end):
while start < end:
yield start
start += 1
print(my_range(1, 5))
print(list(my_range(1, 5)))
@thick cape :white_check_mark: Your 3.12 eval job has completed with return code 0.
001 | <generator object my_range at 0x7f4a7dc08c40>
002 | [1, 2, 3, 4]
yield actually makes a generator btw
using yield in a function turns it into a function which returns a generator
thick cape
err isn't that what i said haha
tender gust
range returns a range object. not a list.
range object behaves a lot like lists,...
Would those range of objects be numbers?
wet saffron
Putting something in quotes makes it seem like an intentionally false statement for simplicity
thick cape
oh i meant it more as emphasis of a vocab term
boreal kiln
Would those range of objects be numbers?
"range object" ... NOT "range of objects"
tender gust
oh range in is the object?
wet saffron
for here, `yield` in python lets you define a function which is a "generator". a...
You may also be more specific, as a generator is an iterator. Iterators will be exhausted when iterated through
boreal kiln
oh range in is the object?
yes, the range itself is an object, that only stores start, end and step.. it doesn't actually store any of the numbers
wet saffron
iterators are also iterables
frank hare
You may also be more specific, as a generator is an iterator. Iterators will be ...
let's keep it on topic and helpful, they didnt ask about generators
wet saffron
Connor mentioned it in explanation
tender gust
are all functions objects?
thick cape
yes!
boreal kiln
in python, yes. but everything is kinda an object
>>> r = range(10)
>>> r
range(0, 10)
>>> type(r)
<class 'range'>
an object in python is anything that represents data
objects each have a type, e.g. 5 is an int, [5] is a list, range(5) is a range
boreal kiln
are all functions objects?
in regards to range .. the range function (it's actually a class) returns a range object
there is an important difference between range and range(...)
the first is the range class/function itself, and the latter creates an instance/object of that range class.
tender gust
an object in python is anything that represents data
what else would considered a object i know now that all functions are objects
wet saffron
everything
frank hare
strings, sets, floats, dicts, etc
boreal kiln
integers, strings, tuples, lists, classes/types, modules
tender gust
is bob = 4 witch would be the object 4?
frank hare
True, None
wet saffron
ints floats lists tuples dicts sets functions modules classes complex numbers
And so on
wet saffron
is bob = 4 witch would be the object 4?
Yes, 4 is an object
boreal kiln
all objects have a type, but types are objects as well, so they gotta have a type. which is called type
frank hare
is bob = 4 witch would be the object 4?
don't get confused between the semantics (what we're talking about here) and the syntax (what you see in your python file, e.g. bob = 4)
bob is a name that, after it's defined, refers to an object
4 is an int literal that creates an object
after bob = 4 is executed, bob refers to the object that 4 created
boreal kiln
is bob = 4 witch would be the object 4?
bob = 4 is an assignment. the whole thing itself is not an object. it's a statement. But the right side of an assignment is an expression, and expressions are always evaluated to some object (in this case 4 is an integer object)
tender gust
im still trying to reread your guys messages btw
tender gust
a list and a range have different string representations
what is a string repersentation?
like the whole two words?
frank hare
when you try to print an object, you want to see something, ideally some characters that tell you about that object
!e
print(range(2))
@frank hare :white_check_mark: Your 3.12 eval job has completed with return code 0.
range(0, 2)
range(0, 2) is the representation of the range object, but those characters are not what the object is
on some level the object is just some binary data handled by the python interpreter
so in short the string representation of an object is the string you get when you ask for it (and the print function implicitly asks for string representations for it to print)
tender gust
So we use the list function with the range function because we want a string repersentation?
because the range func doesnt do it on its own
frank hare
we use it bc the list's string representation shows the numbers inside, and the range's does not
tender gust
oh okay : D
tender gust
we use it bc the list's string representation shows the numbers inside, and the ...
inside the range function right?
frank hare
the list's string representation shows the objects inside the list, the range's doesn't show the numbers "inside" the range
and there's a good reason for that, which people were talking about earlier
tender gust
are numbers inside the list objects
tender gust
So i wrote in my notes: WE use the list func because list's string repersentation show the numbers inside the range func
is this right?
frank hare
yeah
tender gust
and string repersentation is a property of the list func?
frank hare
every object has a string representation
tender gust
im lost at what you said lol
frank hare
you know what a string is?
frank hare
a string representation of an object is just the string that represents the object
if it didnt have one, you couldnt print it
so every object has one
tender gust
a string repersentation is just a printed statement?
pure spruceBOT
@frank hare :white_check_mark: Your 3.12 eval job has completed with return code 0.
<object object at 0x7fd412854400>
!close
pure spruceBOT
Python help channel closed