Big Questions

Sometimes, people have great questions that aren't covered in the course and take too long to answer during the practical sessions. This section is for those questions.

Why is the course teaching coding using the Python language?

There are lots of languages to write code in. We chose Python over other languages for these reasons:

1. It is Simple to setup.
   Other languages can require some complex setup or other dependencies to get started.
2. It is Easy to start writing code.
   Just printing "Hello world!" can be complicated in other languages. Python is also designed to be readable, which is crucial.
3. It is Capable of professional level code.
   Python is used at all kinds of companies including Google and Microsoft. This course isn't aimed at getting people qualified for a job, but Python is a very common language that employers are looking for.
4. It is widely adopted and used for learning.
   Beyond this course, students might want to explore coding themselves. There are lots of great Python courses available online such as this Udemy course.
5. It supports multiple programming paradigms.
   Python code can be procedural, object orientated or functional.
6. It is a garbage-collected language.
   This means it handles the low level clean up of memory, so you can concentrate on learning the high level concepts.

How does the Python code relate to ones and zeros?

This is very simplified and probably incorrect in parts, but very roughly...

The ones and zeros are actually numbers, they are just a different representation system. '1000111' in binary is '71' in decimal. Here's an article for information on the conversion and representation. We use binary because the computers we use are built with electronics that use a 1 for 'on' and a '0' of off. This simplification means we can make the electronics very small and very fast.

The computer has data and operations it can perform to transform the data. The data has a location, known as the address, and a value. Operations are simple, such as move data from one address to another, or add two pieces of data and so on. The data, the instructions the computer uses and the addresses are all binary numbers. Using binary for everything makes writing code very difficult. This is what it looks like to print "hello world" in machine code (reference): Note that it actually uses Hexadecimal, which is another way of representing numbers, used here as it's more compact than binary!

        b8    21 0a 00 00   
        a3    0c 10 00 06  
        b8    6f 72 6c 64  
        a3    08 10 00 06   
        b8    6f 2c 20 57   
        a3    04 10 00 06  
        b8    48 65 6c 6c   
        a3    00 10 00 06  
        b9    00 10 00 06 
        ba    10 00 00 00  
        bb    01 00 00 00  
        b8    04 00 00 00   
        cd    80            
        b8    01 00 00 00  
        cd    80           
      

To make this easier, Kathleen Booth created assembly language to represent the ones and zeros as instructions in English. These instructions are compiled into ones and zeros that a machine can use. This language was much better to use, you can see in this example how to print "hello world!" to the screen.

        hello: DB "Hello World" ; store string

        start:
        MOV AH, 0x13            
        MOV CX, 11             
        MOV BX, 0               
        MOV ES, BX             
        MOV BP, OFFSET hello    
        MOV DL, 0              
        int 0x10               
      

This was still not ideal and a bit tricky to read and comprehend at a glance. To help with this readability problem, several languages where created. They also had a compilation step that converted them into the code the machine could understand, but they had a simpler syntax. C and Fortran are good examples.

        #include 
        int main() {
            printf("Hello, World!");
            return 0;
        }
        

In Python we simply write this as

        print("Hello world")
      

Which is great!

But how does Python get turned into ones and zeros? This is complicated, as Python as a language, is a standard, not a specific program or tool. Similar to a dictionary or instruction manual, Python is defined as special words and what results they should produce. This standard is implemented by lots of competing organizations and companies. Each implementation has its own benefits and drawbacks. A common implementation is CPython, which is an interpreter written in the C language, that converts the Python into bytecode and executes that on a virtual machine. I'm going to stop explaining at this point as my own knowledge runs out, and also because it gets very, very complicated.