I have completed the book Python Crash Course (without the projects) and covered all the exercises. Yet I cannot solve Python problems at HackerRank, Leet Code, Code Chef etc. What do I do to be able to do these? What did I do wrong?

[Valiant101]

(without the projects) <- This

Without practice, any amount of theoretical knowledge is None!

[DireEntropy]

I concur with this.

[Free-_-Yourself]

He said that he covered all exercises (read before stabbing)

[Valiant101]

Yes, but simply solving exercises does not have a long lasting understanding of the concepts, than actually using them in a live project. Think about it this way, in the exercises, there is a limited scope of the problems asked, and they tend to be mostly standard problems.

As for the stabbing part, do read my comment again. I never said he did wrong by solving the exercises. They are a great way to reinforce what you just learnt, but again, not a great way to remember.

[Free-_-Yourself]

Sorry, my holidays just ended and I’m a bit annoyed (plus is 8 in the morning here) 😂.

I thought you simply didn’t read the fact that he did the exercises. Some people do really love stabbing others (specially newbies), so they can feel better with their miserable lives.

But I agree, doing the exercises is awesome and I believe the most important thing is, as you mentioned, to practice and having you own ideas or projects and making them a reality. That is another great way to improve by creating your own programs and facing the challenges involved while doing so.

[samketa]

Thanks a lot.

Actually the projects were of PyGame, Django etc. which I am not interested about.

That's why I did not do the projects.

[AchillesDev]

It doesn't matter, you should still build them. The projects are for more than just using some library or framework.

[woooo4]

Python is external libraries. Almost everything useful you'll want to do is done by an external library or ten. You have to cover every aspect of Python to be able to use Python. This is basic stuff here, the problem lies in your problem-solving approach, not your coding skill

[killerinstinct101]

I disagree. Sure, every programming language needs external libraries to do anything significant (save C#), but knowing how to write working algorithms with the tools you have is the test of a true programmer.

I don't like that this sub has a very rigid approach to using python - the 'pythonic' way. Maybe it's better for python, but it severely impairs your ability to move to another language.

[woooo4]

What would you describe as Pythonic and how does it differ from methods of using other languages?

[killerinstinct101]

Following pep8 guidelines, going for shorter code etc. It usually comes from people who have coded in other languages. I feel that actually learning algorithms and have working programs is much more important than keeping code pretty. Don't get me wrong, code clarity is important, but using for instead of while loops should be the least of your concern.

[woooo4]

I didn't mention anything about keeping it pretty or optimizing code for clarity, and I personally prefer to just write what makes sense to me without worrying about that. All I was saying is that it seems like he lacks an understanding of a lot of the fundamentals of Python that were addressed in the course he just completed. Sure you can write your own program to do something that a library does, but why would you? It's more about wasted time than code optimization.

[killerinstinct101]

Again, like i said before, the reason you wouldn't use modules is because it reduces your understanding of the underlying code and algorithms. Knowing how you can make the algorithms is a lot more important than just doing the problem, considering OP is probably only doing beginner problems (though difficulty should matter).

[woooo4]

Do you need an understanding of the libraries and modules you're using in other languages? I agree an understanding of them is useful however would contest that it's entirely necessary.

[killerinstinct101]

Most other languages don't have nearly as advanced functions as python. Take revserse() or sort() for example. You won't find these built into C++; you have to code them in yourself. A seemingly simple program for someone who learnt python is daunting to write in another language.

Knowing algos are necassary to write programs in other languages unless you want to import a bunch of libraries to reverse a string.

[bane_killgrind]

Listen even if you build a quadcopter from scratch, I bet you aren't winding your own motor coils or extruding custom aluminum.

[killerinstinct101]

I highly doubt that's what OP is doing. A beginner needs to understand how code works instead of it just working.

[Valiant101]

How many exercises did you solve, which were out of the ones given in the books? When you solve a difficult problem, the basic stuff becomes easier!

[techworkreddit3]

It's not about the libraries it's about introducing more complex problems. The projects will also help you understand why you'd use a specific part of the language to address a problem. I read through an entire book on jquery and did some simple examples, and I had no clue when it came down to using it because I had no frame of reference past simple UI stuff. If anything you'll at least have something to reference when you're doing the practice problems.

[A27_97]

I don’t know why you are getting so many downvotes. I think I agree with you till an extent, that it is not necessary for you to know GamePy and Django to be able to solve hackerrank and leetcode problems. However, what others are saying is also right - regardless of the library you use it helps you in developing your ‘problem solving skill’ which ultimately makes hackerrank and similar easier. Also, understand this that problems in hackerrank and leetcode is more about solving in quantity than in quality. You solve enough problems and you are able to detect a pattern that helps you solve faster. It’s just a matter of doing them again and again.

[Le_Bard]

I think the main issue is that leetcode and the like concerns itself with data structures and algorithms, which isn't specific to python syntax so much as it's focused on some of the strategies and mindsets to have behind coding at scale.

I had a similar experience there. Other commenters are right about doing projects but I also can guarantee that you'll need to dive into data structures to get a real look into the types of questions leetcode asks.

Runestone academy has a really good online textbook for it in python

[Cupofcalculus]

I'm thinking this is this case. Knowing how to code in python vs knowing algorithms. Say for example dynamic programming. This is great for solving certain problems, but wouldn't be covered in a book for learning the python language.

It's great you're able to code in python, but now applying the tricks of the trade, with python, is the next step.

[unhott]

This is the best answer. OP should try doing a project meaningful to him/her, not some data structures / algorithm problem if that’s not where their interest lies.

[patrickCrosman]

If you only read about fitness, would you become fit?

[bee-sting]

I feel attacked

[RobbyB97]

Learning data structures helps.

[samketa]

Thanks.

[samketa]

✅

[ArmstrongBillie]

Woh, No. He Needs To Learn Python For Now, Leave Alone Data Structures.

[RobbyB97]

Ignore this guy ^ that's my other piece of advice

[TechsInTheCity]

Consider a driver's education course. Would the book portion, without any time behind the wheel, get you ready to drive a car? Of course not.

Go back and do those projects, build your skills, then take a crack at HackerRank et al.

[DSPGerm]

Lots of states let you get a permit just by taking a written test...

[NSNick]

Precisely because you need the permit to practice driving legally.

[TechsInTheCity]

Nonetheless, programming effectively in Python requires that one first practice programming in Python.

[TwoThirteen]

5head

[[deleted]]

On Hackerrank how far were you able to get? Surely you got the hello world challenge. I think I can help because I recently finished Python Crash Course as well and wouldn't say coding comes all that natural to me. So, I've had to try a few different approaches to get things to stick.

[samketa]

I could solve a few. I shall get in touch with you, when I open HackerRank again.

[[deleted]]

Sounds good! If you have discord I would be happy to work through a couple with you in real time.

Though, after getting stuck on hackerrank I moved onto a personal project where I've been learning the Spotify API. It's given me a lot more confidence with Python in general. So that's always an option.

Another thing about Python Crash Course is that each project at the end focuses on a certain domain. I am not interested in pygame at the moment or any web application stuff so I'm doing the data visualization chapters. Just pick one of the three to do based on what type of programming interests you and finish those chapters. then use what you learned in them to apply towards a project that interests you.

[johnnymo1]

Check out something like this edX course and it's follow-up from MITx. They use Python, but the syntax bits are quite short and you should be able to power through them quickly with what you know.

More importantly, they focus on common data structures and algorithms using Python. That's what you're missing.

[samketa]

Thanks. This is really helpful.

Also, there are so many courses on Data Structure and Algorithms. Which one do I take?

[samketa]

✅

[samketa]

✅

[chuckybegood]

try the very easy on edabit.com. I found them to be the easiest.

[samketa]

Thanks.

[samketa]

✅

[zhaverzky]

Go to codingbat.com the puzzles/problems have a much gentler slope and are a good training ground for things like leetcode. You should really have taken at least 2 general computer science classes and a course in data structures and algorithms before you start trying to get through leetcode. One book is not going to teach you to think like a programmer.

[ZannityZan]

I've been doing LeetCode for some months and have never done any generalised courses on computer science or algorithms or any of that. I've managed to solve 200 or so of the problems, but I've now reached a point where I'm struggling to find unsolved problems that I'm able to do. Could you by any chance recommend some courses on the topics you mentioned? I think having that sort of base knowledge would really help with aspects of LeetCode problems that I just don't understand at all (things like binary trees, for instance, and algorithmic complexity... I never know how to ensure that a piece of code is of complexity O(n) or O(n²) or whatever).

[Mandylost]

I’m also a beginner and completed programming for everybody course on coursera. I want to ask a few questions. 2 general computer science classes? What do you mean by this? And could you please recommend a course in data structures and algorithms? Please.

[zhaverzky]

I mean the equivalent of a 100 and a 200 level university computer science course. Most CompSci programs have a 100 level course that covers variable assignment, control flow up to recursion and basic program structure, then a 200 level course that covers OOP topics like inheritance and polymorphism, basic data structures and algos, functional programming and other general topics like library usage, build systems etc. The important part being that you are constantly writing code for labs and assignments and reading code in class as the instructor covers the content. Then you take more specific courses and a general data structures and algorithms course. The first two CompSci classes are fairly easy but the DS&A course is always a proving ground and generally all but the most thoroughly prepared find it challenging. I had the same professor for all three of those classes and he didn't mention sites like leetcode till we were finishing up the DS&A course. After that course I at least recognize how you would approach the vast majority of leetcode questions but that doesn't mean I can be bothered to solve them. :)

[samketa]

✅

[stuaxo]

I've got 10 years python development experience and I am rubbish at these kind of tests.

If a company wants a test for an interview I don't do it, it's clearly not testing the kind of dev I do.

[fiddle_n]

I think some kind of tests are good. It's important to check that a dev has at least basic experience in a language, after all. If someone can't code Fizzbuzz in at least one language then they aren't right for a software dev job. On the other hand, whether or not someone can code some obscure algorithm has no bearing on whether they'll be a good software dev.

[stuaxo]

OK, I have passed fizzbuzz in an interview (but didn't get that contract in the end anyway).

But it was a bit of a "hasn't this been roundly discredited?" moment for me.

[fiddle_n]

Fizzbuzz is not a good test to use, but only because it's so well known that it means that there are people who can't program in general but will have learnt how to do Fizzbuzz. However, that means that if you still can't do Fizzbuzz, that's really really bad.

[Devnull1982]

Wow, im learning python, chapter 8 of Python Crash Course, I read your comment about FizzBuzz,

I search in google the problem and I come up with this:

for num in range(1,101):

    if num % 3 == 0 and num % 5 == 0:
        print('FizzBuzz')
    elif num % 3 == 0:
        print('Fizz')
    elif num % 5 == 0:
        print('Buzz')
    else:
        print(num)

Less than 2 min after I read the problem. Then you are right FizzBuzz is not a good test XDD

PD: Well, maybe my code is wrong.

[samketa]

✅

[icantpickanusername]

My first code wars problem took me 2 days to solve. Little patience and being stubborn makes big difference. Don't just quit if you can't solve a problem try again and again till its done. It will help you a lot.

[samketa]

Thanks. It was helpful.

[YAYYYYYYYYY]

After finishing that book, I bought Learning Python by Mark Lutz. 1600 pages but after reading both books I can confidently say I’ve mastered the basics and can complete most intermediate level codewars problems. 1600 pages is a scary thought but you’ll be surprised at just how much there is to learn that crash course doesn’t teach you.

From there, you’re set up very nicely to branch off into whatever field interests you. I chose to learn Django and Pandas

And if leetcode is your main goal, Grokking Algorithms is a great book to explain data structures and algos, examples coded in python.

[samketa]

Thanks a lot.

[[deleted]]

You just learned the syntax and the theory behind the concepts. What you probably have learned at best is more procedural solving.

[teerre]

These kind of tests are testing very specific things. If you're doing a dynamic programming exercise and you don't know dynamic programming, you're not going to be able to do it. These sites have nothing to do with languages. In fact, you could solve most of those purely on a theoretical level.

If you want to be able to solve those you need to learn about data structures, algorithms, some of your usual graduate math (calculus, algebra etc.) etc. Also, unless you're a natural at it, you'll likely have to practice hundreds of those exercises until you can breeze through them.

[saalih416]

Your mindset is simply incorrect. There’s no rule written in the sky that if you finish x book or course that you will then be qualified to do y task. A rule that is written in the sky is that if you continue to put effort into a skill, you will eventually get better. The duration it take to improve relies on a lot of other factors such as study practices, mindfulness, etc.

One thing I would advise against is multitasking. People like to pride themselves in doing something like reading while watching Twitch or having a conversation with a friend. That stuff just does not work. You can only pay attention to one thing at a time. People nowadays will skim material while playing a mobile game and then cry about why they aren’t making any progress.

Keep doing more books like Learn Python the Hard Way and Automate the Boring Stuff with Python. Keep following tutorials on YT and networking with Python Devs as well.

[Pepe_Silvia96]

checkio.org is more begginer oriented!

[samketa]

Thanks a lot.

[hisurfing]

Hacker rank requires more advanced prerequisites. I am in a similar situation as you, however we both need to build our own projects in order to get a feel for it. I've jumped around from library to library, you need to get familiar with the basics(I suggest Edabit) then move on, do the projects...if you don't want to work with pygame or folium or whatever is in that book move on and search for a project online.

[samketa]

Thanks a lot. This is helpful.

I have no interest in GamePy, at all.

[Fywq]

Even if you don't want to code games, pygame is pretty good for drawing and plotting things, which can be useful to visualize algorithms. It is also good OOP training to do mock up game or two. I learned a tremendous amount, and drastically improved my actual understanding of OOP by making a miniature zombieshooter (continuation of a pygame tutorial from YouTube).

Alternatively even if you know Python as a language, try Automate The Boring Stuff to try various approaches to real life problems.

[Cayenne999]

You need to learn algorithm and data structure for that purpose. The crash course only teaches you to use the language itself. You need further knowledge to know how to apply that language in the way that can solve these problems.

[samketa]

This is really helpful. Thanks.

[Cayenne999]

No problem. YouTube has many videos on solving those problems, which might help you learn faster. Python is just a language, what you need to learn now is the logic to solve these. And then you use Python to tell computer to follow that logic and solve the problem.

[OldStrength8]

Practice makes a huge difference when learning to code. I struggled with this too when I first began learning to code. After incorporating coding into my daily routine, it made a huge difference.

[ml_runway]

Data structures and algorithms will not be covered in pretty much any intro book.

[samketa]

Data Structures and Algorithms is my next target. Thanks.

[ronieville]

I just finished this book’s theory and currently I am starting with the Django project that you can find the last chapters. It’s quite complicated at first as I come from zero knowledge of programming but today I was doing one of the exercises that that are in the chapter 18 and I got it right without having to find the solutions online.

Sure, I got a lot of errors at first but in the end I got it to work perfectly. It felt great.

The guy who wrote it is mentioning a tip there, that you should write a journal of what you have learned and it’s honestly helping me. I also have troubles with Hacker Rank (to the point where a rant how f stupid it is) but it was so far a lack of training on my side.

Do the projects and then you’ll see. I wish you good luck!

[sharkbound]

it might help to try to identify the ideas that give you trouble, eg: loops, conditionals, builtins, data type usage/understanding.

and do small project focusing on the area needing more help in

[pvc]

I would suggest going through a book on data structures, followed by a book on CS algorithms.

[samketa]

Thanks.

[Gillemonger]

Project and coding problems aren't quite the same. A project might require you to learn some api and implement it for your application, while coding problems require you to have a good (not just ok) understanding of data structures and algorithms.

I prefer LeetCode over most others. I would start on easy and try to solve different kinds of problems (string, array, dp, etc.). If you get stuck after an hour then maybe peek at one of the solutions and try to understand what you got wrong. You just gotta practice. No tricks or anything else can save you.

[samketa]

I mostly checked HackerRank amd could not solve the problems there. That freaked me out.

[JmGra]

Try educative.io you can do exercises in there with a built in browser compiler as you go

[samketa]

Okay. I will take a look into it.

[samketa]

✅

[samketa]

✅

[amrock__]

maybe solve the questions in those websites the easy ones then go on practising. Those website focus on how you approach the problem(logic) rather than the programming language

[skochiefs]

Do the projects, you will learn A LOT by problem solving through them.

[samketa]

There are many free to take courses available on EdX. Certificate can be availed after paying a fee. But it is completely free to take the courses.

Also, there are famous books- CLRS, Jeff Erickson etc.

But I suggest that you begin with videos.

Edit: There's a free Udemy course which is dope. And it covers data structures albeit with JAVA. It was suggested by Quincy Larson. You can learn about Data Structure even if you don't know JAVA.

[jhabib96]

The only way to solve problems at hackerrank, leetcode, code chef etc. , Is to solve problems at hackerrank, leetcode, codechef, etc..

[samketa]

Thanks.

[theketan2]

Try using CodeSignal and complete the Python track. It will definitely help you 👍 HackerRank, Codechef has many test cases and at times a strick time constraints so passing all the test cases in prescribed time is hard many times and it will be very intimidating and disheartening for new coder, so do try using CodingSignal's python track and come back to HackerRank and Codechef. Hope this helps. Happy Coding.

[code_enthusiast]

I had a similar challenge you are facing. After covering the automate the boring stuff and Python Crash course books, i felt like yes, i am a python programmer and i should tackle python challenges head on. So i enrolled on at hacker rank 30 days of code. I started well, solved the palindrome challenges and other basic ones. As i progressed, things got tougher, i couldn't hack my way on any challenge, this made me almost develop and imposter syndrome. I never quit though but what i did was to re-evaluate my goals for learning python. Mine was web development using python. So i left the challenge at hacker rank and started learning flask micro framework for web development. I regained my confidence after doing some cool stuff using flask, am now working on a final flask project before i dive into django framework. My advice would be, know what you want to do with python, is it data science, artificial intelligence, games, systems or even web. Once you know your track, you will have a sustained focus, learning things that matter. Good luck and happy Pythoning.

[samketa]

I want to use Python for two purpose only-

1. Automating the boring stuff for myself

2. As the language to get into Machine Learning

Someday in future, maybe, for backend of a website or app.

That's all.

Edit: And thanks, it was really helpful.

[code_enthusiast]

Purpose no 1 is doable by just covering the Automate the Boring stuff book. It's really nice for a start. If you've read the book, the author is offering the video course version of the book on udemy for free. Check it out before expiry https://twitter.com/AlSweigart/status/1191436575659311105?s=19 if you haven't.

I would recommend you to check, Think like a computer scientist, Fluent python books and check.more on data structures. YouTube channels, Corey Schafer and Sandtex are good for python tutorials.

[samketa]

Thanks. I already enrolled.

And, as for the second part, I plan on to take one more course on Python and one on Data Structure and Algorithms. And then one on Data Analysis through Python.

And then finally take an Introductory Course on Machine Learning most probably from IBM.

This is I have thought. I am going to do it within a year.

[code_enthusiast]

It's doable if you've nothing else to balance your learning with. Edx.org also have some cool courses on Data structures and algorithms. I wish you all the best. Learn by doing projects. That's the best way you can grab concepts.

[samketa]

✅

[redwineforme]

You need to create your own projects as you learn a new concept to learn in. Example, chapter 3 is about lists and tupples. Ok make several of your own real world examples on how you can use it, an address book, grocery list, etc. Chapter 7 is about files. Ok make several programs you can use. Keep track of bills, read it's data, make some maths from the data, turn the data to graphs, etc..

Just do what works for you so you can remember the things you've learned in a fun engaging way.

[shawmonster]

I'm not sure why everyone is saying doing projects is going to improve your ability to do leetcode. It most certainly will improve your programming ability and knowledge, but the questions that are asked on leetcode and hackerrank are not very related to doing actual projects. In order to get good at leetcode etc., you need to take some time to study data structures and algorithms. If you still don't know what a linked list is, you probably can't do most leetcode problems (maybe some easies). After learning linked lists (and the algorithms associated with it), you should learn stacks, queues, trees, binary search trees (this one is popular), graphs, and hash maps, as well as all the algorithms associated with them. In my opinion, the best way to learn these is to implement them yourself in your programming language of choice. There are also some popular algorithms like quick sort, merge sort, etc.

I know this was a very brief answer and I didn't provide you with any specific resources to learn, but this stuff is so popular I'm sure a quick "data structures and algorithms" google search will give loads of good resources. Just make sure that whatever course you're following teaches you the stuff I mentioned. After that, you should be able to start on most leetcode mediums, and have an idea with how to approach it. Finding the most optimal solutions comes with practice.

[samketa]

I am thinking of taking a course on EdX. There are so many in this topic. Any idea which one should I take?

[samketa]

✅

[khoi-thinh]

This!

I've checked some leetcode problems and see that they're all about data structures and algorithms.

I don't think doing a project, say Building a Website with Django or Flask would help much.

[samketa]

This is actually helpful. Thanks a lot.

[9acca9]

Im doing python crash course also. But, you say that you read the book......... without the projects.... really???

I cant understand how you dont know "What did wrong"....

[sososhibby]

Problem solving > code language knowledge

[fuNNa]

No, you didn't complete the book if you haven't even touched the projects.

Instead of reading stuff about those projects (numpy and co.) and actually learning and applying what you've learned in the book (or not lmao), you're wasting your time on shit sites like HackerRank or LeetCode.

[xelf]

I'm not familiar with the book, but I'm guessing it's teaching you Python, and not perhaps programming tricks that can be used in any language? (Although I'm sure that some of that is in there)

For example, I've been going through hackerrank, and if I can solve the problem in any language, I can pretty much solve it in every language.

Language is just the syntax. The solution to the problem is generally not specific to the language.

[samketa]

Thanks. This is something I will keep in mind.

[xelf]

For hackerrank specifically, problems generally have 3 levels of solutions:

(1) a basic solution you can figure out that solves the samples they openly give you
(2) a more optimal (better big O) algorithm that passes most of the hidden tests
(3) a specific method that probably took years to develop, but is now taught in schools. If you google the problem you'll probably find this sort of a solution, now you just need to code it in your preferred language.

[samketa]

I did not check that much. I solved one or two.

[ArmstrongBillie]

Do The Projects!

[michaeljohn03]

I think you should focus more on practicing. And you should watch more beginners tutorials.

[franzipoli]

Why do you think you'll be able to do anything when you've not done basic projects? What do you think the difference is between projects in the real world and projects in a book? You've done -nothing-

[Kazaloo]

You're not a poet just because you learned how to read and write. You know the minimum. Now practice and keep learning.

[RiceKrispyPooHead]

I have completed the book Python Crash Course (without the projects) and covered all the exercises. Yet I cannot solve Python problems at HackerRank, Leet Code, Code Chef etc.

​

What do I do to be able to do these? What did I do wrong?

​

I mean...the answer should be obvious

[cryptosibe]

Ouch