Understanding PHP Syntax

What is PHP?

PHP is one of the most used back-end languages in the web. In terms of functionality, it lets you do pretty much what any other back-end language lets you. The syntax is pretty similar to JavaScript, and its biggest strength is the community – you can find tutorials and documentation for everything you do.

PHP has proven to be a great survivor: 82% of the web uses PHP. Is the second language with the most interest from Google. In a stack-overflow 2018 developer survey, PHP was the most popular language amongst PHP, Ruby, Nodejs and Python. PHP Frameworks are phenomenal: Laravel, Phpixie, etc.

JavaScript vs PHP

PHP and JavaScript are like Apples and Oranges. In terms of functionality, they have NOTHING in common: they don’t serve the same purpose, they don’t do the same things, they come from different backgrounds, etc.

The only things that they have in common are:

You can do the main logical operations and control the flow the same way: Like in any other programming language, you have loops, while, if..else, switch, etc. (PHP has even more options – we’ll talk about those later).
They have almost the same syntax:You have to end every line with a semi-colon; functions are declared the same way; loops are declared the same way; logical operations are the same; etc.

Data-Types

There are only a few differences – here is the explanation:

In JavaScript	In PHP
Number	Instead of one number data-type, you now have two: Integer and Float. An integer does not have decimals: `$myNumber = 23.23; //float` `$myNumber = 54; //integer` `$myNumber = 12.00; //float (even with 00 as decimals).`
Undefined	The undefined data-type is not available in PHP. Here undefined and null are the same data-type. `$myNumber; //is null because it was not defined`
Array	They have both numerical index arrays and associative arrays. The difference is that JavaScript calls "Dictionaries" the PHP associative arrays. `$array = array('Juan','John','Steven'); //array of numeric indexes` `$array = array('SSN-55532323' =` //associative array, using strings as indexes instead of integers.
String	Is the same in PHP.

Printing values

Console.log is amazing in JS, but in PHP, you will have to use echo for simple data-types, and print_r to print more complex data-types (like arrays and objects).

With JavaScript

var simpleValue = ‘hello’;
console.log(simpleValue);
//This will print the content of the variable
var arrayValue = [‘Hello’,23, 76, ‘World’,43];
console.log(arrayValue);
//This will print the content of the array and its elements.

With PHP

$simpleValue = ‘Hello’;
echo $simpleValue;   //this will print the content
$arrayValue = array(‘Hello’,23,76,’World’,43);
echo $arrayValue;   //this will not work
print_r($arrayValue);  //this will work, printing the content of the array in a format like this:
CopyArray
(
    [0] => Hello
    [1] => 23
    [2] => 76
    [3] => World
    [4] => 43
)

Working With Arrays

PHP started as a functional-programming language and still has a lot of things that will work in functions instead of objects. That is why it is very important to review the basic array operations; the syntax may look different, but, in the end, they have the same purpose.

Looping Arrays

With JavaScript

for(var i = 0; i<myArray.length; i++){
console.log(myArray[i];
}
myArray.forEach(function(item,index,array) {
console.log(item);
});

for($i=0; $i<count($myArray);$i++){
print_r($myArray[i]);
}
foreach($myArray as $item){
print_r($item);
}
foreach($myArray as $index => $value){
print_r($value);
}

Adding and Removing Items

With JavaScript

var myArray = [‘Academy’, ‘Coding’];
myArray.push(‘4Geeks’); //Adding an item
//to remove the item in the INDEX position
myArray.splice(index, 1);

With PHP

$myArray = array(‘Academy’,’Coding’);
array_push($myArray, ‘4Geeks’);  //adding an item
//to remove the item in the index position
unset($myArray[index]);
$myArray = array_values($myArray);

Sorting Functions for Arrays

With JavaScript

const myArray = [2,5,1,4,7];
myArray.sort();  //sorts array in ascending order
/* Example output
[1, 2, 4, 5, 7]
*/
myArray.reverse();  //sorts array in descending order
/* Example output
[7, 5, 4, 2, 1]
*/

With PHP

$myArray = array(2,5,1,4,7);
sort($myArray);
print_r($myArray);  //sorts array in ascending order
/* Example output
Array
(
[0] => 1
[1] => 2
[2] => 4
[3] => 5
[4] => 7
)*/
rsort($myArray);
print_r($myArray);  //sorts array in descending order
/* Example output
Array
(
[0] => 7
[1] => 5
[2] => 4
[3] => 2
[4] => 1
)*/
$myAssosiativeArray = array("SSN-9232323" => "Ramon Cornell", "SSN-5643233" => "Steban Dido", "SSN-5554433" => "Mikelly Reik", "SSN-3423344" => "Bob Stalin");
asort($myAssosiativeArray);
print_r($myAssosiativeArray);  //sort associative arrays in ascending order, according to the value
/* Example output
Array
(
[SSN-3423344] => Bob Stalin
[SSN-5554433] => Mikelly Reik
[SSN-9232323] => Ramon Cornell
[SSN-5643233] => Steban Dido
)*/
ksort($myAssosiativeArray);
print_r($myAssosiativeArray);  //sort associative arrays in ascending order, according to the key
/* Example output
Array
(
[SSN-3423344] => Bob Stalin
[SSN-5554433] => Mikelly Reik
[SSN-5643233] => Steban Dido
[SSN-9232323] => Ramon Cornell
)*/
arsort($myAssosiativeArray);
print_r($myAssosiativeArray);  //sort associative arrays in descending order, according to the value
/* Example output
Array
(
[SSN-5643233] => Steban Dido
[SSN-9232323] => Ramon Cornell
[SSN-5554433] => Mikelly Reik
[SSN-3423344] => Bob Stalin
)*/
krsort($myAssosiativeArray);
print_r($myAssosiativeArray);  //sort associative arrays in descending order, according to the key
/* Example output
Array
(
[SSN-9232323] => Ramon Cornell
[SSN-5643233] => Steban Dido
[SSN-5554433] => Mikelly Reik
[SSN-3423344] => Bob Stalin
)*/

The Switch Statement

This is almost identical to the switch statement in JavaScript:

With JavaScript

favcolor = "red";
switch (favcolor) {
    case "red":
    return "Your favorite color is red!";
    break;
    case "blue":
    return "Your favorite color is blue!";
    break;
    case "green":
    return "Your favorite color is green!";
    break;
    default:
    return "Your favorite color is neither red, blue, nor green!";
}

With PHP

<?php
    $favcolor = "red";
    switch ($favcolor) {
    case "red":
    echo "Your favorite color is red!";
    break;
    case "blue":
    echo "Your favorite color is blue!";
    break;
    case "green":
    echo "Your favorite color is green!";
    break;
    default:
    echo "Your favorite color is neither red, blue, nor green!";
}
?>

Objects

When working with objects, we have to use the operator "->" instead of "." to access the object properties.

With JavaScript

var auxCar = new Car();
console.log(auxCar.brand);

With PHP

<?php
    $myCar = new Car();
    echo $car->brand;
?>

All the other Operations

All the other operations are pretty much the same as in JavaScript. Just use the dollar $ sign at the beginning of each variable, and use the arrow to access object properties instead of the dot .