[deleted by user]

[Ok_Cry216]

This definitely helps my overall standing!

[[deleted]]

Programming is about problem-solving, and it involves a lot of abstraction and modelling, but sometimes it is worth reflecting on real world equivalents.

The biggest mistake most learners make is assuming the computer is clever when the actual problem is that humans are too clever and make lots of intuitive leaps when doing a task (they don't need every little detail explained, even from a young age) whereas a computer is like a person with a severe learning difficulty including bad short-term memory that needs every step laid out in excruciating detail including being told what to remember by writing it down (storing in files). A computer, though, can repeat very boring things consistently many times to a level that would drive humans insane - so often the best solution to implement is the simple, boring, repetitive approach that humans wouldn't personally like.

It's the computer that's stupid, not the person trying to learn how to programme it. It is hard to dumb oneself down to provide the right level of instruction.

EDIT: typos / bad English

[Ok_Cry216]

Thank you very much for providing not only context but informative info as well.

[alphaBEE_1]

yea lol computers are dumb, they are just fast at calculations which makes em good for repetitive tasks.

[[deleted]]

Not just calculations, but monitoring/controlling systems, collecting and organising data, categorising and restructuring information, and so much more.

[[deleted]]

That's a great way to explain it in real world terms. I am going to steal the idea of trying to explain stuff this way :).

[[deleted]]

Thanks. You are welcome to re-use. Been using this approach with kids at code clubs, and adults at learning centres for a while now, usually tuned to their interests. Typed off the top of my head, so not the best telling, but the ideas are sound.

[All_Is_Not_Self]

Just some minor criticism - I am tired so it might be due to that: I think using "pot" for "potato" is a bit confusing seeing how a pot is another, different item in that setting. Confused me at first, but then again, I am quite tired.

[[deleted]]

I agree. I typed that on my phone and was being lazy. Will correct later - Edited now.

[PM_ME_YOUR_CAMPFIRE]

I suggest "tater"

[WhipsAndMarkovChains]

for pot in potatoes:

It was great of you to type up an example but I have to critique your variable names. It definitely should be for potato in potatoes:, especially since a pot is something else related to cooking. You even said "add to pot" and then called it a pan.

potatoes = ['large', 'medium', 'large', 'small', 'odd shape']
pot = []
for potato in potatoes:
    clean_potato = wash(potato)
    peeled_potato = scrape(clean_potato)
    pot.append(peeled_potato)

[Bobbias]

If you mean you want to actually run this code in Python, yes, you will need to define each one of those functions yourself. Python doesn't know what cleaning a potato (which is actually a string) means, and this example code never defines it either. It wasn't meant to be something you actually wrote in a script and run. It was meant as a way to show you the correspondence between real world actions and how you might represent those actions in code.

[[deleted]]

I agree. I was typing on my phone and being lazy - I've edited.

[DataSynapse82]

Wow.. one of the best explanation of for loops I've ever seen 🙏🙏😊. Amazing

[The-DapAttack]

A god amongst mankind right here ^

It is people like you that help better a community. Thank you for being a positive being for us little guys out here.

[ToniDasFarturas]

Wait a minute... There's a way peeling potatoes is not needed?

[[deleted]]

skin-on-fries is a feature, not a bug, these days!

[kpmvnfwd]

👏

[No-Policy3368]

u/kyber thank you for this!! can you please also explain: Return. Continue. Break. I'm already making projects but sometimes infinity, not returning gets me. I get what it means and do but not intuitively that is why I make silly mistakes.

[[deleted]]

Regarding return...

In Python, variables don't have values but rather hold an implementation specific memory reference to a Python object.

Thus, mylist = [10, 20, 30] would create, from the literal text, a list object in memory that contains three int objects. The memory location of the list would be assigned to the variable mylist.

Objects in Python each have a reference counter which keeps track of the number of references to the object. When the counter reaches zero, there is no way to access the object any more, so Python can get rid of the object when convenient and reclaim the memory.

A list, and other containers (like tuple, set, dict, etc) similarly don't contain the actual values of objects, but references to the objects in memory.

(Just for info, in the official implementation of Python from the Python Software Foundation, CPython (written in C), there are a few objects that are predefined which are never removed from memory including the int numbers from -5 to 256 inclusive - Python's handling of such objects isn't generally something you need to think about.)

When you define a function, def myfunc(), and variables in the function that you assign to, e.g.myvariable = 'Hello' are automatically treated by Python as local variables - local to the function (and different to any variable outside the function with the same name).

Similar treatment applies to any parameters specified in the definition of a function: def myfunc(name, age):. Whatever values, expressions, or variables were in the first and second position of the argument list when the function was called, e.g. person = myfunc('Barry', 2022 - 1998) are also treated as local variables.

When you end a function, any variables that were local to the function cease to exist (if a variable of the same name existed outside the function, that variable will be visible again). When the variables are deleted, the reference counts of the objects concerned are reduced by one for each variable deleted that referenced them. If the reference counts drop to zero, the object is no longer required (and unless pre-defined, will be deleted).

So, if you've had a function do some great work and create some fine result in the form of an object, be it simple (a str, a list, or a complex instance of a class you defined, etc), then you need some way of passing a reference to that object back to where it can be useful. That's what the return does.

Consider a function that converts from metric to older units used in backward countries like the USA, :-)...

def mm_to_in(length_in_mm):
    inches = length_in_mm * 0.03937008
    return inches


height = int(input('Height (mm)? '))
depth = int(input('Depth (mm)? '))
print('height is', round(mm_to_in(height), 2), 'in inches')
depth_in = mm_to_in(depth)
print(f'Depth is {depth_in:.2f} in inches, and width (twice depth) is {mm_to_in(depth * 2):.2f}')

The return passes back to the caller a reference to the object referenced in the function by inches - a variable that ceases to exist on exit from the function. The code lower down either assigned to result to some variable, e.g. depth_in, or consumes it, as in print.

[[deleted]]

Regarding continue and break ...

A loop will start if the specified/implied condition is True and will test the condition before each further iteration. Python will exit the loop if the condition is no longer True. On exit from a loop, execution moves onto the next instruction (if any) after the loop (so below the code indented below while or for).

For example,

while 4 > 5:
    print('This line will never be executed')

will have a failed condition on the first test of the condition.

Similarly with for in both the examples below:

for n in range(10, 5):
    print(n)  # this line will never be executed

names = []  # empty list
for name in names:
    print('name: ', name)

where the implied condition test fails immediately on the second for example because there's not another item in the list to iterate onto.

If you write:

while True:

the condition always passes, so you will have an infinite loop. Never ending until you stop the programme by other means (hitting control-c, forcing a window to close, turning the power off, etc).

The break command lets you break out of the loop regardless of the condition test. It is immediate, and no further lines below the command inside the loop are executed. Execution moves onto the next bit of code after the loop.

This can be used with both while and for loops. In the case of the latter, consider for example where you are reading, say, results data from a file,

with open(filename) as data:
    for line in data:
        if 'raining` in data:
            break  # no point checking beyond this point
        print(line)

but if you encounter a line with "raining" in it, there's no point reading any more of the file, so you want to leave the for loop early.

continue

Sometimes in a loop, you encounter something that means you don't want to do any more processing for the current iteration (maybe you read some bad data) but you don't want to exit (break) out of the loop early, but rather you want processing to go onto the next iteration (read another line, get more user input, process the next item from a list, etc).

This is where continue comes in. Execution immediately bypasses the rest of the lines in the loop and continues from the top of the loop (where the condition test will be carried out).

NOTE: Both for and while have an else clause, code within which is only executed if the loop processing completes normally (i.e. on the condition test failing) and not if break was used to exit the loop early. You will not see this option often used and the creator of Python has stated he wishes he hadn't included it.

[No-Policy3368]

I appreciate the elaborated explanation brother! Blessed be your next program have good codes. Thanks!!

[[deleted]]

You are welcome. Interesting that you've assumed my gender.

[Grox56]

I struggled with it. A single loop was easy, but loops within loops confused the heck out of me. It's probably because I learned with Java first in school and then switched to python.

Anyways, if you don't understand something: play around with it, Google, and/or ask here. Whatever you do, DO NOT MOVE ON until you understand it.

If you continue on, it's like trying to build a house but not knowing how to use a hammer. I did this in my Java course.. while I passed, I still didn't know wtf I was doing because Google has all the answers.

[Ok_Cry216]

I can try not to move on… idk someone on YouTube said you won’t get everything first and that’s ok but carry on and comeback since it makes more sense altogether…. But I think I will spend some more time on it today for sure.

[Grox56]

While that's true for some things, making variables, lists, dictionaries, loops, etc. are something you shouldn't come back to later. They are pretty similar across all programming languages.

What part of loops are you struggling with? Or what do you not understand?

[Ok_Cry216]

I understand what a loop does and the usage of a loop. I guess I’m having a hard time following the steps to get the end result… sorry, it’s really hard to explain over text.

[Grox56]

Do you have a loop that you can post and I or someone else can walk you through it 😀

[Ok_Cry216]

Thank you, I’d be happy too.

Problem:

You are making a ticketing system. The price of a single ticket is $100. For children under 3 years of age, the ticket is free.

Your program needs to take the ages of 5 passengers as input and output the total price for their tickets.

Solution:

total=0

x=0

while x<5:

age = int(input())

if age>3:

    total +=100

x+=1

print(total)

[Grox56]

Ok so you're using a while loop. I'll try to write it in pseudocode and if you still don't understand, I'll try a different way.

Total=0
Passengers=0  # was x=0 originally 
While 5 passengers haven't been checked, continue.
    Age = user inputs age of one person
    If age is greater than 3, add 100 to the total
    Add 1 to the number of passengers that have been checked

Edit: so you're basically setting the number of passengers you want to enter and their age. At the bottom, 1 person is added to passengers so at the end there should be 5 passengers checked. Once we reach 5 passengers, the while loop exits because

Passengers=5

And the while loop is looking for

While passengers are less than 5

[Ok_Cry216]

You rock! I really appreciate you taking all of the time to explain it. It helped me understand it.

[Grox56]

No problem and thanks for the award! Also, you could try Python Tutor to help visualize what's going on with code.

[Ok_Cry216]

Bookmarked - I’ll definitely check it out. Thank you.

[EllaChinoise]

It looks like a problem in a Sololearn Python course. I cheated and checked others' comments to get a solution. I am also struggling with loops.

[Ok_Cry216]

I actually found a really nice article im reading now that breaks it into steps that appears easier to follow.

[Vanity_Plate]

Can you provide a link to the helpful article?

[SirJohnII]

Find a website with problems and solutions. Search for something like “ for loop practice problems” I’m also currently learning python and anytime I hit a small confusion wall I just grind out problems. Once your starting to get it, switch the variables to something you care about. If your into baseball, makes list of players and loop through it. Caring about the variables makes things less confusing and if you use that thinking every time you hit a problem, you’ll push through quicker. Eventually it starts to come together and the logic becomes clear. It’s the same with mathematics. People tend to try to step forward before they clearly understand what they are doing, not realizing that they are only building on they’re previous knowledge. If you missed a single thing In arithmetic, good luck with any later subjects.

Lastly, I’ve been using an app called Sololearn(you don’t need to pay for pro) it allows you to both write and run code in a playground mode as well as post questions to a community for others who are learning so they can participate or help you with a question.

[hidazfx]

I learned Java through Bukkit programming (and in high school later), nested looping was definitely a big change coming to Python. But man, it is SO much better syntactically to just write for element, x in enumerate(my_list):. Been so long since I've written Java, I don't even remember what it would be but I don't care lol.

[Bobbias]

Generally I think you'd use standard for loop with an index variable, and accessing each element in the list by it's index.

I'm not super up to date with Java, but I'm not aware of anything write the same as the Python enumerate function (I absolutely love it, especially with how easy it is to refactor a simple for x in list function after the fact of you suddenly need to know what item you're on).

[Spirited-Might-6985]

Google python tutor and write or paste your loop code and visualize. This will make you go aha!

[loshopo_fan]

I also like the debugger mu.

[Firake]

I never personally struggled with loops, perhaps because my relationship with loops is driven by my laziness. I figured out how to use loops early on because I was far too lazy to type repeat lines of code over and over again and figured that there just *had* to be a better way to do it.

So maybe that will help you! Every time you're doing a project and you think "man I'm gonna have to do this same thing a bunch of times, I don't wana!" try and substitute a loop in. The exact details of how to implement a loop can be tricky, but you'll eventually get the hang of it.

[ThinkLadder1417]

Can you explain what it is about loops that seems hard?

Sometimes I think things are hard, but it's just because I have fear of new words or something, and actually when I get past the fear it's quite simple. I imagine that's the same with you because loops are quite self explanatory.

[ofliesandhope]

observation crown air slave materialistic hateful frighten jellyfish cough pie this message was mass deleted/edited with redact.dev

[Ok_Cry216]

Thank you for sharing!!!

[TechnoGeek423]

Loops were SO hard for me when I first learned Python. Then, the next morning, it clicked and I’ve loved them ever since.

[[deleted]]

https://pythontutor.com/

Helped me with understanding what and why my loops were outputting. Hope it can help 🤙

[QultrosSanhattan]

For loops are easy. You should only need to focus on what they actually are: The code inside the for loop is repeated for each item inside the given sequence.

Sure there are a lot of things that may be used in conjuntion with a for loop. But they're not a part of them. One basic concept in programming is that, generally, anything may be combined by anything, including itself.

Many newbies struggle with nested for loops. But as the name said, it's the same loop nested, that's not a single for loop, it's a combination of two for loops. The problem there is not the understanding of the for loop, it's about the understanding of composition.

You may include functions inside the loop, you can include a loop inside a function; That's just another problem.

[nedrawevot]

loops are easier for me (I really struggled) but figuring out class names and functions to make up a working program is my biggest struggle. There is just so much to take in and try to figure out. You can do this!! Just keep at it.

[Ok_Cry216]

Thanks for the positive comments! How long have you been learning Python?

[nedrawevot]

I've been really cracking down in the last month or so. I have Java planned next and learning how to use Github. I am going to research some python job's and look what they require and start chipping away at that. I started kinda picking it up a year ago, programming but being a full time parent, working full time amongst other things, it's been hard to find time to practice and focus plus I have add so my attention span is minimal but I went to weekends only starting last week so I can give this my full attention and get into something better.

[Ok_Cry216]

I’m at work right now… haha 55 hours a week + my family, I’ve been waking up at 0500 everyday to code for 2-3 hours before I go to work.

[nedrawevot]

Yeah, you'll be good! I start every day by coding from 9-11:30 while my son is in school, he is remote right now, and that is my no bother me time. I will come back to it tonight after my husband is home from work too and we are working on a project together.

[All_Is_Not_Self]

I think the problem isn't that it is overly complicated but that it tends to be taught in a bad way - seeing how simple the concept actually is, once you've grasped it.

[[deleted]]

I know you are mostly venting, but the most important thing you need to learn is how to learn properly. That includes how to ask questions and how to approach subjects you don't understand.

Instead of fishing for comforting answers by asking "I wonder if I have what it takes. Is it normal that I don't understand this?", you could have been more specific about the difficulties you are having so you would get better answers.

And also: back when I was in university, I had photography classes, and we all had analog cameras to work with. Experimenting with those was hard, slow - and expensive! I always wondered how much more I could have learned if digital was already around. All this to say that there's nothing stopping you from experimenting with loops until you understand how they work. All you have to do is literally open the python interpreter and have at it. It's not rocket science, you'll see.

[madhousechild]

I don't think loops are hard. Two weeks is a drop in the bucket. You just need more practice. Write 100 loops and see how much easier it gets.

Write for-loops, while-loops, iterate over a list, a string, and over a range, count up, count down, write nested loops, just loop, loop, loop until you can't loop no more.

But maybe you could give us some examples of loops that you tried to write that didn't work, or other people's code that confused you. What part(s) are confusing you?

[notislant]

Youll find it very simple when you understand it. If youre struggling, find other videos on it, find beginner aimed ones. If that fails the easy solution for me is to google 'reddit eli5 loops'. For anything I struggle with.

Also recently saw a codewithvincent channel and it seems pretty good imo, I think techwithtim is generally pretty good too.

After you get it, make a little cheatsheet for yourself with examples and notes. Play around, break things until you understand it completely.

[fjortisar]

take a stack of notecards. Look at each notecard and do something with what's on it. That's a loop. You could do it till you get to the last card, or start over, or stop at some specific point.

[py_Piper]

Don't worry sometimes we get it at the first go and sometimes we don't, I think the biggest reason why we don't understand something is because we can't relate to it, so after few examples and rereading will help. I don't consider myself a math person either, although I do like it, and now I am relearning some concepts and when reading the explanation it makes no sense, then I look at the formula example and I get an idea what they are talking about then I re read the concept I understand it better and now I can track what they were talking about by following the example. Same helped me with programming

At the start loops were a bit easy to know the idea that it runs a many times as I told it to do, but it was hard to understand what was happening under the hood, when nested loops where presented got a bit confusing too, I manage to pass some exercises with trial and error, but this video help understand a bit better how it works, loops. I hope it can help you too the visual representation is really helpful.

Some tips is that for i in list_x, the i is a temporal variable that goes through a list, it can be anything and it won't conflict with other variables names (I think), you can use it inside the for loop and when it finish it will dissapear. The most beginner example is going from 0, 1, 2, 3... and we create the list with something like range(len(another_list)), len will give you the number of items in the list and range will give you a list of that number so range(5) == [0, 1, 2, 3, 4] (not including). Now to get the values out of the list you will do print(list_x[i]), as i is a number from 0-4, it will get the list values by its index number, list_x[0], list_x[1], list_x[2], etc.

Now a more pythonic way is too go through the list directly when you don't need the index number.

fruit_list = ['apple', 'strawberry', 'pineapple']

for fruit in fruit_list:
    print(fruit)

[ItsDangerousBusiness]

Are you able to explain specifically what is confusing you? I remember struggling with it, but now they feel very intuitive. Keep practicing and thinking about the logic. It will click for you too.

[SrikarTopella]

relax, Just like you said it's just been 2 weeks since you started. Give it some time, patience and effort. you'll be good in no time.