Lesson 2: What is a real world problem?

One of the biggest problems that most people face when they are trying to progress towards a goal is finding problems to solve. Working through a textbook or a course where there are problems laid out for you takes away a lot of the required work. Having the problem presented in such a way removes a great deal of the thought required because in the real world, problems aren’t generally so simple to find. For example, when you are getting your education everything is laid out for you in the form of a curriculum. You have a certain amount of courses that you have to pass and the grade which you need is also decided by the administration. There is not thinking involved in deciding for yourself what is an acceptable grade to get to pass the subject, but rather you just have to focus on learning the material in the class and pass the tests. This eliminates a lot of the thought processes that you need and makes questions such as “why” unnecessary. If you asked why do you need a certain grade to pass, then the answer will most likely be that it’s set by the education ministry. A situation like this is similar to a “sandbox” in the development world. This is used to refer to an environment that isn’t real, but functions like a real environment in which there are certain constraints on what can be done.

There are very logical reasons why education is structured like this, so this is in no means a disparagement on the educational system. However, what tends to happen is that when you need to make decisions where the problem isn’t laid out clearly then it’s difficult to know where to start. This is to be expected if you haven’t been trained specifically for that. For example, if we look at education versus the job market, there is a stark difference in how the two need to be approached. When you have finished your education - whether it’s high school or university - you need to find a job. There is no formula to find a job that is comparable to the formula used to get students educated. You can pass a certain number of courses after which you get a degree at university for example, but you cannot go to a certain amount of job workshops then automatically get a job. The job market doesn’t work like that. Instead what a job workshop does is show you how the market works in the real world. From that you have to do some investigative work to find out where you can get an opportunity. This is an important difference between the job market and educational system because you have to decide where you start and what “grade” is acceptable.

It is, therefore, important to learn to prioritize what is the most urgent problem and solve that first. In the job market example, your first priority is to get a job because you either get a job or you are jobless. The first option is good and the second option is bad. Contrast that to deciding between two jobs that you could get. In that case, both options are good, so while there is still a choice that needs to be made, it’s different from choosing between being jobless and having a job. The same applies to other decisions in life and especially decisions in programming.

Decisions in programming

Up until now, we haven’t discussed anything directly related to writing a program. This has been intentional because the exercise in this section is going to address that. Programming is actually better described as problem solving and the four components of computational thinking is a guide on how to do that. So, you actually have been learning to program - although you need to learn the practicalities of it now. Programming languages are simply ways in which you can communicate the plan you have designed to a computer. The computer then does the work and what appears on the screen are the results. This could be what you expected or it could be unexpected. Based on what appears on the screen, you can continue with your plan or adjust it if there are mistakes. You repeat this process until the main problem is solved. We are going to learn to program in Python, but the programming language is largely irrelevant because writing code is similar to writing a book. There are two components that are important to writing a book: the structure and the language. The structure is the way in which the book’s narrative flows and the language is the words that are written on the pages. In the same way, computational thinking is the structure of the program (the logical flow) and the programming language (the characters on the screen) are what brings that structure to life. They are both necessary and there can be errors in both, so it’s important to understand how they work together.

What is an error?

The way in which programming languages work vary depending on the language, but all programming languages produce error messages when something has gone wrong. A lot of new programmers get intimidated with error messages because it may seem like they have failed in writing their code. The error messages usually seem intimidating with a bunch of text on a red background, but getting an error message isn’t a failure. It simple means there is a mistake in your program and the error message is giving you a log of where it could be. Usually the last line of the error message is where the immediate problem is that’s preventing the program from running. Learning to understand what these error messages mean takes some time, so don’t worry if it seems overwhelming at first. In 90% of cases, you can enter the last line of the error message in a search engine such as Google or a website such as Stackoverflow and there should be an answer similar to the one you are looking for.

There are many different kinds of error messages, but for the sake of simplicity we can divide them into two categories: errors which stop the program from running and logical errors. When you have written some code that violates the syntax of the language then your program will not run until you fix the problem. To use an analogy to explain this, image you write a Tweet, but before the Tweet gets published it checks if your spelling and grammar is correct. If it’s not correct then it shows an error message with the line where the spelling or grammar error is located. You have to correct the mistake and resend the Tweet. That is similar to how programming works in that error messages are just showing you where a mistake is and once you fix it then you can proceed.

On the other hand, a logical error is one in which your program runs, but it’s not doing what you expect it to do. If we go back to the Tweet example, in the case of a logical error, the Tweet gets send without any errors, but the actual writing doesn’t mean what you intended it to mean. This type of error is the most difficult to find because it doesn’t stop the program from running, so you have to understand why the program is not doing what you intended. When you find the error it could be some big mistake, but usually it’s the smaller mistake that are more difficult to find. For example, if you are trying to calculate the average of two numbers, but instead of the correct answer you get a much larger number. You later find out that you multiplied (*) the two numbers together instead of adding (+) them together. These kinds of errors are very common and just like any other problems in life their causes are usually quite straightforward: you were distracted and didn’t notice the error, you were tired and didn’t focus when you wrote the code; you were nervous to make a mistake, so you made a mistake, etc.

The best way to deal with errors that you can’t seem to fix is to take a break from the code and do something else. Come back to the code at a later time and look through it with fresh eyes. Often you will notice things that you didn’t notice before and this could help you to solve the problem much easier. The main takeaway from error messages is that you mustn’t be overwhelmed by them, they are there to help you find the error and they don’t indicate you have failed.

Exercise 1

The first exercise you are going to actually program without knowing how to program. Sounds impossible, right? Well, it’s possible if you understood the previous lessons. Just like in the real world, the task is not going to be laid out perfectly, but rather you have to decide what is the best way to do it. In programming languages, it’s customary for the first program to print the words “Hello world!”, so to keep with custom, your task to print “Hello world!” to the screen using the Python programming language. You can do this whichever way you want, but the following are a few tips

Think about Occam’s Razor (the simplest solution is usually the optimal one).

Don’t ask anyone for help - if you get frustrated then take a break and walk around. The point is for you to solve the problem, not someone else.

If you have tried absolutely everything and you can’t figure out the answer, then read exercise hint 1.

Exercise 1 hint 2

Read the exercise hint 2 fully before trying anything. In order to write Python code, you need to install Python on your local machine, create a .py file which contains the code you want to run and execute the code via the command line (or terminal). For example, you can create a file called hello_world.py and run it from the command line using the following command python hello_world.py. There are a few steps in this process, but each step could have several problems. For example, it won’t work if you don’t have Python installed on your computer. If the hello_world.py file is not in the correct directory then it also won’t work. If you haven’t written the commands correctly in the file, then it won’t run properly. If you haven’t got the right version of Python then you might have to use python3 hello_world.py, so python hello_world.py won’t work in this case. You might not even know what a command line is, so this simple task can seem overwhelming again even if you’ve done all the preparation as laid out in the previous lessons.

Well then what can we do if even the most simple exercise is so complicated? We take a look at the original question which is:

Print “Hello world!” to the screen using the Python programming language.

In the the exercise there is no mention of installing anything on your local machine and there are no requirements for setting up any environment for writing Python code. So, since we have access to the internet, we could look for ways in which to write Python code without the need for setting anything up. In recent times, there have been a lot of websites that have been created to help people who are coding or learning to code. Since it’s difficult to understand what a piece of code is doing without seeing the results, many developers have used the latest technologies to create coding environment within browsers. This means that they can write Python (or other programming languages too) on designated sections of their websites then press a button and the code executes (in other words, the program runs). This makes it easier for people to share code and show other developers the problems they are facing, since they can run the code themselves in their browsers without the need to set everything up.

Of course, the complexity of these environments differs from website to website, but usually the basic functionality works well. So, the easiest way to solve the current exercise is to look for online Python editors. This eliminates the need to install anything on your local machine and it also eliminates errors that could be caused from different operating systems (Window, Linux or MacOS). If you have made it to this point and you still cannot solve the problem then take a break, do something else and come back to it with some fresh eyes. If you are still have trouble after that, then go on the exercise hint 3 where I will provide a solution to this problem.

Exercise 1 hint 3 (solution)

The easiest way to do this exercise is to simply search “online Python editor” in Google and the first few results will show you such an editor. Here are the websites that I got when I searched this phrase Programiz, Online Python and OnlineGDB. All of these websites allow you to write Python code and execute the code by pressing the run button. There you have it, you’ve just written some Python code.

Now that you have it running, you can play around with the code. It’s always good to experiment with what’s going on because I could explain to you every detail, but it might not make sense to everyone. When you are working with the code yourself, you can experiment with changing the code and observe how the results change. So a few things you could try is remove some elements of the code and see what happens. Replace the quotation marks (“) with apostrophes (’), does the code still run? More importantly is it still giving the expected output? What happens when you remove the last close round bracket )? Does the code still run or does it give an error? Can you replace the round brackets () with square brackets []? If you get an error doing this then can you draw the conclusion that for a print statement you can use round brackets and not square brackets? One final experiment you can try is deleting everything from the window and retyping it from memory. Can you get it running again or does it give an error? If it gives you can error, can you understand the error message?

You don’t have to answer the questions above or you can try other experiments. The point is to get it working then break it then fix again. This is all to make you think about what’s happening and what the results are if you change the code in a certain way. That being said, if the process can be so simple, then you might be wondering what’s the point of setting up a Python environment on your own computer? For starters, if you don’t have access to the internet then you can’t run anything online. However, more important than that, the online Python editors are usually very basic and don’t include more advanced packages and libraries that you might need. So, when you are working on developing programs for specific tasks, you will need to set up environments of your own, but remember to keep it simple. If all you need to do is print a simple sentence then the online editors are sufficient. A big component of programming (and problem solving in general) is to get the best results, with the least effort in the most efficient way possible. As was discussed previously, though, you won’t always achieve this because of time, lack of knowledge or other constraints. So, don’t worry about that for now, but rather focus on getting it working and keeping it simple.