Strings

Korvin

Integers and Floats

Booleans

This section should be fairly empty, since $sectionBoolean is set to:bool(false)
Set it to true and this section will expand

Arrays

Let us echo and var_dump our array $names[], currently empty: Array
array(2) { [0]=> string(5) "David" [1]=> string(4) "Mary" }
echo $names[1] returns: Mary

We have a multi-dimensional array

array(2) {
  [0]=>
  array(3) {
    ["username"]=>
    string(4) "Korv"
    ["email"]=>
    string(13) "km@korvin.org"
    ["likes"]=>
    array(2) {
      [0]=>
      string(7) "history"
      [1]=>
      string(4) "food"
    }
  }
  [1]=>
  array(3) {
    ["username"]=>
    string(4) "Mary"
    ["email"]=>
    string(16) "mary@hotmail.com"
    ["likes"]=>
    array(2) {
      [0]=>
      string(5) "books"
      [1]=>
      string(4) "cats"
    }
  }
}

Let's see if we can access the second user's email.
mary@hotmail.com

Now let's use a foreach loop over the $users array.
Korv Mary
We could use the same technique to output the list of email addresses:
km@korvin.org mary@hotmail.com
and likes?
history,food books,cats

Now lets add a new user and modify a record.
Users: Korv Mary Jeremy
Likes: history,food books,PHP reading,cooking

Null

Null represents a variable with no value; the variable has either been set to NULL, has been unset, or has never been set in the first place. Earlier we set $noName to null. Let's var_dump($noName): NULL

Now let's set and echo the variable: Name

Now let's unset and var_dump the variable: NULL

Now let's set the variable back to NULL, since that's best practice: NULL

Concatenation and Variable Parsing

The current weather is rainy and it's 30.6 degrees
The current weather is rainy and it's 30.6 degrees.
The current weather is rainy and it's 30.6°

If statements - days of the week

In the codecourse video, an integer is set, and an if..if else statement run on the integer as a condition.
We can grab the same integer from the php function getdate(), which returns an array of data about the current date. Running an identical if..if else statement outputs: Wednesday, the middle of the week!
In this case, the only advantage the if statement confers is the ability to echo a different message for each day. If we just want to output the name of the day, with getdate() we can do it in 2 lines of code. Wednesday

As the video explains, if we do need condition checking, it's more efficient to use inbuilt array functions. We can illustrate the difference clearly in our code if we aim to output some more abstract information, such as a god associated with the day.

Today's deity: odin

To nest or not to nest

If we want to output a string, and then ouput something if the string exceeds a defined length, we can do it with nested if statements:
Success! A name exists! It is Korvin.
If at all possible however, avoid nesting if statements. The same effect can be achieved more readably with an inversion operator:
A name exists! It is Korvin.

Calculating percentages

This section covers addition, multiplication and division, using the + - and * operators.
Total lessons in course: 35 You have now completed 18.2 lessons. That's 52.0% of the course.

Subtraction

Uses the - operator.
Current balance: 12000 Item cost: 250.65 Your balance after purchase will be: 11749.35

Structure of a FOR loop

For loops iterate according to initiator, condition and increment. Given two variables - $totalItems and$itemsPerPage, we can use the for loop to output the number of pages needed.
25 items per page / 66 items.So we need 3 pages. Voila: 1 2 3

We can also use a for loop to loop through an array; although a foreach loop is preferable, this can have some use-cases
David Mary

WHILE and DO...WHILE loops

We can iterate over an incremented variable using a while loop 1 2 3 4 5 6 7 8 9 10

But a more practical use would be a dice game
Target: 3
You rolled: 5 You rolled: 1
You rolled the target: 3

Be careful. The following would cause an infinite loop:

  while (true){
    //do something forever
  }

do..while loops will run at least once, before condition checking occurs

FOR...EACH loops

There's an example of this in the Datatypes section. It's expanded below to make use of the index values to give us an ordered list.
0: km@korvin.org
1: mary@hotmail.com
2: jem@jem.org

Now let's use a similar technique to loop through a complex array that's 3 levels deep

Topics

Breaking and continuing

Sometimes a loops needs to be broken out of, or skipped. We can easily do this using two keywords: break and continue. The following examples use break for speed, to stop the loop once the desired result has been found, and continue to skip a particular member of the same array.
array(3) { ["username"]=> string(6) "Jeremy" ["email"]=> string(11) "jem@jem.org" ["likes"]=> array(2) { [0]=> string(7) "reading" [1]=> string(7) "cooking" } }
Korv
Jeremy
Xen

Using nested foreach loops, we can find the first user who likes philosophers to be: Xen