#My brain being dumb, scroll on

1 messages · Page 1 of 1 (latest)

misty trench
# 
def InsertionSort(l):
    for a in range(1, len(l)):
        b = a
        while (b > 0) and (l[b-1] > l[b]):
            l[a], l[b] = l[b], [a]
            b -= 1
    return l

print(InsertionSort([9, 8, 3, 5, 4, 6, 0, 1, 2]))


Exception has occurred: TypeError
'>' not supported between instances of 'list' and 'int'
  File "pp.py", line 13, in InsertionSort
    while (b > 0) and (l[b-1] > l[b]):
  File "pp.py", line 18, in <module>
    print(InsertionSort([9, 8, 3, 5, 4, 6, 0, 1, 2]))
TypeError: '>' not supported between instances of 'list' and 'int'

@amber topaz
@echo zodiac

echo zodiac
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what's l?

misty trench
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list

echo zodiac
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i mean
The list you're giving it

misty trench
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the function parameter

echo zodiac
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Ah wait I'm blind

misty trench
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i see

#

@misty trench

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im blind wtf is wrong with the code

amber topaz
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i think i found a fix

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give a sec

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@misty trench done

misty trench
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enligthen me

amber topaz
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i converted it to an int

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and also theres a slight issue in the next line

# 
def InsertionSort(l):
    for a in range(1, len(l)):
        b = a
        while (b > 0) and (int(l[b-1]) > l[b]):
            l[b], l[b-1] = l[b-1], l[b]
            b -= 1
    return l

print(InsertionSort([9, 8, 3, 5, 4, 6, 0, 1, 2]))
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this should be it

misty trench
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wait wot

amber topaz
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kekw

misty trench
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why does l[b-1] return a list

amber topaz
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i dont know

misty trench
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hein

amber topaz
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but i dont think thats all the problem contains

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there is a fundamental error on line 5

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you wanna swap l[b] and l[b-1]

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but you are swapping it with l[a]

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check your code

# 
l[a], l[b] = l[b], [a]
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this is what you did

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l[b], l[b-1] = l[b-1], l[b]

this is what you should do

misty trench
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oh yeah right

amber topaz
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works fine kekw

misty trench
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definitely that 🙂 you're assigning [a] to l[b] ... you don't want that.

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that's putting a list with one item inside a list of ints.

amber topaz
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ye

misty trench
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ellie called it right 🙂

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ok so how does this

image.png
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coz this

image.png
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@amber topaz nicely done.

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@misty trench split that statement

amber topaz
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i thought you had been doing this for a while phantom Kappa

image.png
misty trench
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you're assigning two variables in one go, make it into two assignments and tell me what you see

misty trench
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but that is fine

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your code doesn't do that.

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ik ik

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this is why I rarely do dual assignment in one line 🙂

amber topaz
misty trench
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human performance is an issue

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the weird thing is when this weird shit happens both a and b are the same

image.png
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shouldnt there be.. no change?

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pretty sure the swap code is behaving exactly like you told it to. you just haven't run through the code step by step to see why.

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i did that

misty trench
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i dont understand how swapping two elements in a list create an entirely new list inside the former list

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break it down into two assignments, then step over the code line by line with a == b

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you're not swapping two elements.

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that's what you wanted to do

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but the code you wrote is very much not doing that.

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but... a and b are still integers... even if the integers are wrong it should still swap right... just the wrong elements

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ps: I'm not trying to make you feel bad, just trying to get you to see the issue for yourself. 🙂

misty trench
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l[a], l[b] = l[b], [a]

take a moment, breathe in, then write to me in english what that code does please.

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walk me step by step 🙂

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uhhh.. take the element at pos a in list l, and set its value to the value of element at pos b in list l and vice versa?

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tell you want since you didn't do it .. i'll do it for you... this is what that code looks like in two statements:
l[a] = l[b]
l[b] = [a]

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lets make it easier to read

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list[a] = list[b]
list[b] = [a]

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you descrbied the first line

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tell me what the second one does

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yeah thatll just set both list[a] and list[b] to the value of list[b]

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i see whats wrong here

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that's not quite right.

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how should that code look like ?

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uhm

misty trench
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the second line

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oh what thatll just set the value of b'th element of the list to the value of a

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not the value list[a] holds

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but the value of a itself

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yep.

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now you get it. 🙂

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mhm

misty trench
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the first part of that assignment is correct. the second one is not swapping anything and is adding a new literal list with the value of a as it's single item and putting that in your list.

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wait, SON OF A BITCH I THOUGHT IVE WRITTEN l[a]

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if a and b were 1 and 2 your code would read:
list[1] = list[2]
list[2] = [1] <--- that's you inserting a list into a list.

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told u im blind

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this is why:

  • be careful abbreviating variable names. it makes it easier for your brain to see what it wants to see.
  • when code doesn't work, use prints to log the decisions and the data so you can see what is happening - log the decision being made, the data used to make that decision, and also log the data you were expecting if there was any.
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i.. i- should name things better
sorry for wasting ur time
thx for the help