An unusual email

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I am due to continue studying towards my degree in Computing this week via the Open University (which I highly recommend for distance learning in the UK)

As part of this students get assigned a tutor for each module they study, I received my first contact with my tutor for the module Objected Oriented Programming with such a cleverly worded email I thought I would share it here

Dear Object

I know that that isn’t the usual way in which tutors should greet their students but this is an object-orientated programming (OOP) module and you must start to think about everything around you as “objects”.

The module introduces you to the terminology of OOP, which is not too difficult and can be best understood by making reference to the real world.

For example, you have been taught over the years by tutors and I’m sure you think of us all as being very similar – all taken from the same “template”. In OOP we call this template a Class, let’s call it “OUTutors”, and I am a particular “instance” of this class call “yourTutor”.

I’m sure that I will have similar “attributes” to all the tutors you have had in the past – except you may never actually meet me – and I will probably have similar “behaviour” to your other tutors (although I don’t shout very much).

I have “private” and “public” attributes. My private attributes might be my date of birthday and my OU pay. My public attributes that I am happy to share with you are:

yourTutorName: *Redacted*
yourTutorEmailAddress: *Redacted*
yourTutorPhoneNumber: *Redacted*

As an object I understand certain “protocols” in particular, sendEmail(message) to the above email address and I will try to respond with 24hours where possible. You may also callPhone(message) to the above phone number where again I will try to respond within 24hours.

I, on the other hand, see all students as being taken from the class “OUstudent” and you are a particular “instance” of a OUstudent. Like me your instance makes you an object, called studentYourName as I am an object called yourTutor.

On this module we shall only communicate in a limited number of ways: etutorials (learning events); email; telephone and eTMAs. Whichever method of communication we chose we will be passing “messages” to each other. For example, this email is a message between yourTutor and studentYourName. Later you will be sending me your eTMA; this is a message to me and I will send your marks back to you. So you can see that the “objects” yourTutor and studentYourName have similar “methods” by which they can send “messages”.

So, in summary, today an “object” called yourTutor is using an email “method” to send you this “message”, or in OOP terms:

yourTutor.email(email text); …

This I found to be a very entertaining and involving way to introduce the basic concepts of OOP especially for students with no background in a programming language.

Beginners Javascript | FOR Loops

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Now we know how to check and compare value or variables, it’s time to look at loops.

These can be used for lots of things but to start with it can be used to check each value of an array.

the first is the for loop:

var array = [1,2,3,4,5];

for (var i = 0; i < array.length; i++) {
  if (array[i] == 3) {
    alert('there is a 3 in this array');
  }
}

The first part inside the brackets defines a variable to be used in each pass through of the loop it is general practice to use i for this variable and then j,k etc for nested loops as they are not accessible outside of the loop.
The second part is the comparison argument to decide if to run the loop, in this case is i less than the length of the array.
The third part is the action to take after the loop has been executed.

There is are a few different ways that loops are coded that reduces processing required. The first runs through in the same direction but the more cpu intensive part is only done once:

var array = [1,2,3,4,5];

for (var i = 0, var j = array.length; i < j; i++) {
  if (array[i] == 3) {
    alert('there is a 3 in this array');
  }
}

Assuming it doesn’t matter what order the values are processed this form can be used:

var array = [1,2,3,4,5];

for (var i = array.length; i > 0; i--) {
  if (array[i] == 3) {
    alert('there is a 3 in this array');
  }
}

I personally like to use the first version for readability as my code is still small, but choose what bests suits the complexity of the project.

Beginners JavaScript | IF and Switch

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Now making a comparison and executing a different piece of code, depending on the result is going to happen in probably every piece of code you are going to write and there are a few ways to achieve this

IF statements

These are probably the simplest to get to grips with

var a = 1;

if (a == 1) {
  //is a is 1 then do whatever is here
}
//run this code whatever value a is

This code will check if a is equal to 1 and run the code inside the curly braces and then the rest of the code, if a is not 1 it will skip to after the curly brace and continue to run any other code.

What if you wanted it to do something for a==1 but something different for everything else

 
var a = 1; 

if (a == 1) { 
  //is a is 1 then do whatever is here 
  alert('a is 1');
} else {
  //run this code for any value of a that is NOT 1
  alert('a is not 1');
}
//run this code whatever value a is

Now this is better we can run different code for different values, but what happens is you have some code for a==1, some for a==2 and som for anything else?

 
var a = 1; 
if (a == 1) { 
  alert('a is 1'); 
} else if (a == 2) { 
  alert('a is not 1'); 
} else {
  alert('a is not 1 or 2');
}
//run this code whatever value a is

This can be done for lots of different things but it is more concise to use switch when there are a number of expected results

Switch Statements

 var a = 1; 

switch(a) {
  case 1:
    //code to run if a==1
    break; //exits the switch statement
  case 2:
    //code to run is a==2
    break;
}
//run this code whatever value a is

Now suppose you wanted to use a switch AND have some code run if a is not 1 or 2, JavaScript handles this case by having default in the switch which is the code it will execute if it doesn’t match any of the case statements

var a = 1;

switch (a) {
  case 1:
    alert('a is 1');
    break;
  case 2:
    alert('a is 2');
    break;
  default:
    alert ('a is not 1 or 2');
}

Thats basically it for these statements they are very powerful and can be used in many situations including inside repeating sections of code called loops, but thats a topic for another day.

Beginners JavaScript | Strings

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Before we got much deeper I had best cover strings.

Any time you want to store characters/words it will be as a string, a string can be anything from a single character to a novel if you have enough memory to store it.

Strings are shown definitely to variable names by surrounding them in single or double quotes for example

var myString = 'abc' // sets the variable myString to the string abc
var myString2 = abc  // sets the variable myString2 to be the same as (undeclared) variable abc

If a string is to contain quotes there are two ways to achieve this either by preceding the quote with the escape character \ or by using the other type of quote:

var str1 = 'he said "hello" to them'
var str2 = "he said \"hello\" to them" //str1 == str2
var str3 = "he said "hello" to them"   // error

str3 would cause an error as JS would see it as str3 = ‘string’hello’string’ and throw a syntax error, as you can see the error as the whole string is not highlighted blue in the code block

Two or more strings can be added together using the concat() method (see below) or by using the + operator eg:

var string  = 'hello';
var string2  = 'world';

var myString  = string + string2       
// myString == 'helloworld' with no whitespace as it is not added automatically
var myString2 = string + ' ' + string2 
// myString2 'hello world' as there is a whitespace added between string1 and string2

Properties

property function example
.length gives the length of a string including
any whitespace or special characters		 myStr.length

 

As with most things strings are indexed from 0 so the character at 0 would be the first character in the string, this is an important point to remember when using these methods:

Methods

method function example
.concat() joins a two strings together var str = ‘hello ‘;
var str2 = ‘world’;
str.concat(str2) == ‘hello world’
.split() splits an array into an array at whatever char is in the bracket var str3 = ‘hello world’;
var x = str3.split(‘ ‘);
// x == [hello,world]
.includes() checks to see if a string includes a specific string x = str3.includes(hello);
// x == true
.replace() replaces part of a string with another string x = str3.replace(‘hello’, ‘goodbye’);
// x == ‘goodbye world’

These are just some of the basics and I’ll cover more in another post

Beginners JavaScript | Arrays

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Arrays are at a basic level just a list of things and creating an array is as easy as:

var myArr = [value1,value2,…,valueN];

or to create an empty array:
var myArr = [];

To access the data stored in the array you would put the array name then the number of the item in square brackets, arrays are 0 indexed so the first item would be at [0] for example:

myArr[0];   // the first item in myArr
myArr[100]; // the 99th item in myArr
myArr[n];   // the n-1th item in myArr provided n is a number

Arrays can also hold nested arrays as below;

myArr = [ [1,2,3] , [4,5] , 6];

Which would give
myArr[0] == [1,2,3]
myArr[1] == [4,5]
myArr[2] == 6

To access the arrays inside myArr you use double square brackets:

myArr[0][0] == 1
myArr[0][2] == 3
myArr[1][0] == 4

Using this method you can nest multiple arrays inside each other.

You can then use these methods to get information from or add information to an array

Methods

method function example
.length give the number of items in the array myArr.length
.pop() takes the last item from an array myArr = [1,2,3];

myArr.pop(); // 3
.push() adds an item to an array myArr.push(4);

// myArr == [1,2,3,4]
.shift() takes first item from an array myArr = [1,2,3];

myArr.shift(); // 1
.unshift() add an item to the start of an array myArr.unshift(0);

// myArr == [0,1,2,3]

Beginners JavaScript | Basic Quick Reference

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I started my journey on learning JavaScript, there’s a lot to take in all at once, I really recommend heading over to freecodecamp, if you haven’t found it already, as they use a step by step exercises to build your knowledge, but make sure you fully understand it before moving on and don’t be afraid to go over the same lesson multiple times is it helps (I know it helped me immensely at times).
They also cover the html and CSS side of things which helps get ready for building web pages.

I thought I’d create a a few cheat sheets to refer to whilst learning, I’ll start with the basics:

Comparators

= to assign a value to a variable
== is equal to
=== is equal to AND type matches
!== is NOT equal to
< is LESS than
<= is LESS than OR Equal to
> is GREATER than
>= is GREATER then OR Equal to
&& AND
|| OR

Operators

operator use example equivalent to
++ increment by 1 x++ x = x + 1
−− decrement by 1 x−− x = x – 1
+= increase by x += 2 x = x + 2
-= derease by x -= 2 x = x – 2
*= mutiply by x *= 3 x = x * 3
/= divide by x /= 3 x = x / 3

Whitespace and Comments

\n new line
\r carriage return
\t next tab space
// single line comment
/* start of a multiline comment
*/ end of a multiline comment

Choosing my speciality

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Now comes the part I see as the second most difficult part of becoming a programmer, with the first being actually finding content to put in my blog, which is choosing a specialty.

I have thought a lot about what I want to do and as an entry-level programmer I’m not 100% on what or where I want to go with my career, and if I choose wrong will I limit myself to a small pool of clients with no job prospects.

As I said in my first post I am following the simple programmer How to Create a Blog to Boost your Career course and I have come to realise that specializing in the wrong area will still give me the knowledge in the parent area, so I can choose a speciality and switch if I needed to in the future.

So I have chosen to get involved with Node.JS and specifically using a full stack framework Meteor which looks very interesting (even though a lot of the technical information is above my current understanding) as it can be used to create apps and programs that can run on web and mobile applications.

This has allowed me to do more research into how I  can start in this area and it would seem that to get to grips with node.js the best place to start is to learn how to use JavaScript.

So let the journey to JS wizard begin.

Starting my blog

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As my first blog as an aspiring programmer I feel I should start in a suitably progammer’y’ (if that’s even a word) way with:

“Hello World!”

Now that’s out-of-the-way, I want to say that I don’t have a huge amount of experience as a programmer, I’m still doing my degree through Open University (for those who don’t know it’s a distance learning university for those with current employment/life commitments) but I have played around in the past with Linux boxes, RaspberryPi, a little Arduino and the like but haven’t really got into writing any sort of application so far.

I came across a YouTube channel called simple programmer and watched his videos for a few months and decided I should sign up to his free email course about how to start a blog.

One of the ideas that seems very important is to specialize into a particular area of programming which as a relative newbie is a difficult thing for me to. I have a lot of knowledge in the administration of a small business’ IT infrastructure and I am currently developing a Magento2 web store for the company but that is far too broad to be a specialization, I’ve spent a lot of time developing their crystal reports and interfacing with and working with the production Postgresql databases. As it is only a small company they required me to be a jack-of-all-trades and know about all the areas of their IT infrastructure which didn’t allow a great scope to specialise in any one area.

Now I have two things to make a decide on, first what can I blog about as I’m a relative newbie with nothing  (in my eyes) to offer to anybody out there and secondly what on earth can I specialize in.

Well thanks again to simple programmer I found a video that resolved my first problem (it seems I am not the only one in this situation), John talks about how even the learning experience is blog worthy (check out his video below) and the second issue will be the subject of my next post.