#🔒 can someone explain this by dummying it down for me
onyx bramble
boreal imp
I don't know how much more we can dumb it down - did you follow the instructions?
fervent cove
can you write a script that does that first built point?
onyx bramble
can you write a script that does that first built point?
no idea how
native dust
What would you like explained? These are tasks they want you to solve yourself, using range and/or len, so that you get a decent intuitive feel for their use and uses.
If you've got a specific question, ask.
boreal imp
no idea how
Do you know what range does then?
wintry moon
no
onyx bramble
does that print it inclusive
native dust
Just for the exercise, write a loop to print several numbers.
Maybe you should run it.
onyx bramble
Just for the exercise, write a loop to print several numbers.
oh hey cameron
native dust
You can just copy/paste these text sections into the python interpreter.
onyx bramble
You can just copy/paste these text sections into the python interpreter.
whats a python interpreter
native dust
The REPL, the >>> prompt.
wintry moon
range(N), when used in a loop, gives the numbers from 0 to N -1. the number is stored inside the variable (that you usually name i) (that you don't necessarily use itself)
len returns the number of elements in a list
=> range(len(list)) gives 0 to the number of element in the list, which is exactly the indices you can use to get elements from that list
onyx bramble
The REPL, the `>>>` prompt.
i dont follow
onyx bramble
i use idle
wintry moon
that's the REPL we were talking about
onyx bramble
that's the REPL we were talking about
whats REPL
wintry moon
that window
wintry moon
this is asking you to practice loops
how do you make a loop that goes from 1 to 100 ?
native dust
Can you write a for-loop at all?
wintry moon
show us
onyx bramble
idk if im supposed to put a variable to 100
native dust
Make a list: L = [1,2,3]
onyx bramble
or like
native dust
can you write a loop to print out its members?
onyx bramble
so am i suppposed to put 100 in a list
wintry moon
so am i suppposed to put 100 in a list
no
native dust
nono not yet
wintry moon
close but no
native dust
Run it - what does it do?
onyx bramble
im lost
native dust
So: how many times did you expect the loop to run the print statement?
wintry moon
list is something that hold indexes?
no
onyx bramble
So: how many times did you expect the loop to run the print statement?
i guess 100 times
native dust
How many items in the list itself?
wintry moon
not in your code
native dust
Try printing len(L).
wintry moon
for x in [1, 2, 3]:
print(...)
fill in the ..., what do you want to print to have 1, 2 and 3 on the screen ?
native dust
If L=[1,2,3], then each of 1, 2 and 3 is an item from the list.
onyx bramble
```py
for x in [1, 2, 3]:
print(...)
```
fill in the ..., what do you want...
do i do
dense snow
list is something that hold indexes?
imagine a list as a street, each house in that street is an entry/element to said list and every house in that street has an address, said address is what we call an index
onyx bramble
print([0,1,2])?
native dust
Your list is [0,100,1] What are the items? Also called elements or list members - these are just description English terms, not formal things.
onyx bramble
imagine a list as a street, each house in that street is an entry/element to sai...
good analogy
ill try to remember that
onyx bramble
Your list is `[0,100,1]` What are the items? Also called elements or list member...
if i can remember correctly, [0 = start, 100 is end, 1 is how much i want it to increase by
so i guess 0 - 99
which i shouldve changed it to 0,101
native dust
Ok. You're confsing a list with a range.
A list is like the street: it has houses, each house containing a value. The street address is the index, the contents of the house are the value/item.
A range indicates a range of values in an arithmetic progression. range(0,100,1) represents the values 0, 1, 2, ... up to 99.
native dust
which i shouldve changed it to 0,101
101 is indeed what you'd pick as the upper bound to include 100.
wintry moon
range(N) is a street with N houses each of them having as adress a number from 0 to N-1, and each element being equal to the adress
onyx bramble
Ok. You're confsing a `list` with a `range`.
A list is like the street: it has h...
i see
onyx bramble
A `range` indicates a range of values in an arithmetic progression. `range(0,100...
so in this case i'm supposed to use range?
print(range(100))?
wintry moon
if you do that, you print only one object, the range
and you want to print all the elements inside
wintry moon
it's like if I asked a picture of each house and you send me a picture of the whole street
native dust
(from a distance, not showing each house's contents)
onyx bramble
it's like if I asked a picture of each house and you send me a picture of the wh...
i see
dense snow
i love how every1 adding onto this house/street list analogy
onyx bramble
i love how every1 adding onto this house/street list analogy
its helping alot
wintry moon
range needs to be called with ()
range itself isn't really a thing
like we talked about previously
onyx bramble
oh
i = 100
for i in range(100):
print(i)
i guess i got it
do i necessarily need the i = 100?
lost abyssBOT
!e
```py
for i in range(100):
print(i)
```
:white_check_mark: Your 3.13 eval job has completed with return code 0.
001 | 0
002 | 1
003 | 2
004 | 3
005 | 4
006 | 5
007 | 6
008 | 7
009 | 8
010 | 9
... (truncated - too many lines)
Full output: https://paste.pythondiscord.com/257PRHWLWSRNPONRGL6EQF5VA4
dense snow
!e
i = 100
for i in range(100):
print(i)
:white_check_mark: Your 3.13 eval job has completed with return code 0.
001 | 0
002 | 1
003 | 2
004 | 3
005 | 4
006 | 5
007 | 6
008 | 7
009 | 8
010 | 9
... (truncated - too many lines)
Full output: https://paste.pythondiscord.com/E5PNQQ4G4XVIZUVPVMBSDDOB7M
dense snow
as u can see
jolly bloom
do i necessarily need the i = 100?
you can always try and see :)
dense snow
same result
onyx bramble
i see
man i feel dumb for not knowing something so simple
i guess range index list they confuse me
dense snow
man i feel dumb for not knowing something so simple
we all start somewhere
native dust
i guess range index list they confuse me
Yah. A list is just a container for storing values.
You can get at a particular value by its index. Like, the third value has index 2 (since we count from 0).
A range() is for specifying a range of values equally spaced. So range(10) specifies 0,1,2,3,4,5,5,6,7,8,9. What you use those values for is up to you. Maybe they're just numbers to print. May you will use them to index a list. And so on. They're not inherently list indices or anything - they're just numbers.
... and the point of these exercises up the top it to use these things in a few ways. Once you've done that, the confusion should be less.
onyx bramble
Yah. A list is just a container for storing values.
You can get at a particular ...
what are indices
native dust
The plural of index. One index, several indices.
native dust
(a) write a for loop which iterates 100 times and (b) print your name once as the body of the loop
dense snow
its helping alot
ig another way to explain lists is a bucket list if u know what that is 
native dust
Ok. Now, how does that work?
native dust
for i in range(100):
Ok. Now, how does that work?
onyx bramble
Ok. Now, _how_ does that work?
oh hmm
onyx bramble
Ok. Now, _how_ does that work?
name = "John"
for name in range(101):
print(name)
this just printed the 1 - 100 again
it printed 1 - 100
native dust
That's because you used name as the loop variable.
So each value from the range was assigned to name, overwriting your name="John"
onyx bramble
i see
native dust
But I was actually asking: how does for i in range(100) run 100 times? What causes it to run 100 times?
native dust
But why?
native dust
i gets each number because it is the variable name used in the for-loop.
But where do the numbers come from?
onyx bramble
from range(100)
native dust
Right, then range.
So a range is a range object. How does that turn into the numbers given to i?
onyx bramble
isnt that 0-99
native dust
Yes.
That's what it represents.
How does the for-loop know what values to put in i?
onyx bramble
what do u mean
name = "John"
if True:
print("John"* 100)
i know this is really shitty code
but this is one way to print it 100 times i guess
native dust
!e
I mean this:
for obj in (1,2,3), [4,5,6], "abc", range(3):
print(obj, ', for i in obj ->', end='')
for i in obj:
print(" ", i, end='')
print()
:white_check_mark: Your 3.13 eval job has completed with return code 0.
001 | (1, 2, 3)
002 | 1
003 | 2
004 | 3
005 | [4, 5, 6]
006 | 4
007 | 5
008 | 6
009 | abc
010 | a
... (truncated - too many lines)
Full output: https://paste.pythondiscord.com/VM7EWNNN5RXGIGEWADM5O3T3MA
onyx bramble
!e
I mean this:
```py
for obj in (1,2,3), [4,5,6], "abc", range(3):
print(obj...
what about this
native dust
You should follow the link to see the full output. https://paste.pythondiscord.com/VM7EWNNN5RXGIGEWADM5O3T3MA
onyx bramble
You should follow the link to see the full output. https://paste.pythondiscord.c...
saw it
what about this
native dust
saw it
!e
Let me make it more compact:
for obj in (1,2,3), [4,5,6], "abc", range(3):
print(obj, ', for i in obj ->', end='')
for i in obj:
print(" ", i, end='')
print()
:white_check_mark: Your 3.13 eval job has completed with return code 0.
001 | (1, 2, 3) , for i in obj -> 1 2 3
002 | [4, 5, 6] , for i in obj -> 4 5 6
003 | abc , for i in obj -> a b c
004 | range(0, 3) , for i in obj -> 0 1 2
Here we see the values given to i in each of these for-loops.
Where do those values come from?
onyx bramble
Here we see the values given to `i` in each of these for-loops.
Where do those ...
from the variable obj?
native dust
Each of these objects is "iterable" - you can iterate over the object and it gets you values.
native dust
So the for-loop goes iter(obj) to get an "iterator" which is a object which yields values.
Then the for-loop iterates over the iterator by calling next() on it, which yields each value in turn, once every time it is called.
onyx bramble
So the for-loop goes `iter(obj)` to get an "iterator" which is a object which yi...
right
i get the concept of for loop
native dust
does iterable mean it goes over each
Technically, in python, "iterable" means an object you can call iter() on. But the effect is as you describe.
Right.
So when you go: for i in range(100), the call range(100) gets you a range object. The for-loop calls iter() on that object, getting an iterator. That iterator yields the values 0, 1,2,3 up to 99.
And because those are the values it yields, the for-loop runs that many times.
onyx bramble
right
native dust
The point here is that the for-loop knows nothing specific about what object you give it - a string, a range object, a list, whatever.
It just asks to iterate it, and uses whatever the object produces.
onyx bramble
but can u iterate it over a string?
native dust
Yes, it gets you the letters.
onyx bramble
so can u print a name 100 times
using the for loop
cuz im thinking the code is actually simple
you just * 100 the string
native dust
Yes. You give it an object which yields 100 values (doesn't matter what they are) and have the loop body print the name once.
native dust
What, this?
for i in range(100):
print(name)
Oh. That does something a bit different. Try running it.
It computes a new string with the text John in it repeated 100 times.
The output's different.
native dust
You write the code to produce the result you want.
If you wanted John printed 100 times, each on its own line, the simple way is the:
for i in range(100:
print(name)
way (or literally put "John" in there instead of name).
onyx bramble
You write the code to produce the result you want.
If you wanted `John` printed ...
oh that works too?
native dust
What you could do is say:
- to print
Johnon a line you write the lettersJ o h nand then a newline character (to go to the next line) - make a string containing that, 100 times:
john_lines = "John\n" * 100 - print that single string:
print(john_lines)
onyx bramble
What you _could_ do is say:
- to print `John` on a line you write the letters `J...
i feel like what u just did earlier is so much easier
native dust
oh that works too?
print() whatever expressions you give it.
onyx bramble
which one is called "efficient" coding
native dust
i feel like what u just did earlier is so much easier
The for-loop with a single print() call inside it? Yes, which is why we usually wite it that way.
native dust
which one is called "efficient" coding
Porbably the for-loop with the single print().
onyx bramble
The for-loop with a single print() call inside it? Yes, which is why we usually ...
i see. i'll stick with that
native dust
It is more important for code to be clear and understandable than to be as "efficient" as possible.
Particularl since "efficientcy" often depends on internals of the language. There may be times when makes one big string is "faster". But I'd imagine they're rare, and it depends on how expensive "making a big string" is. Which we don't knwo without measuring it.
Better to write something clear, and go after performance it that turns out to be important later.
lost abyssBOT
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