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• GitHub is a hosted Git service (version control system)
• It is very popular for hosting Open Source projects
• It is used to "Sign in with GitHub" to a lot of development Tools 

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php-intro-workshop

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What is PHP?

PHP (recursive acronym for PHP: Hypertext Preprocessor) is a widely-used open source general-purpose scripting language that is especially suited for web development [2]

Unlike other scripting languages that run directly in your computer, PHP will almost always run on a server.

Writing our first program

"Hello, World!"

The "Hello, World!" program is the simplest program you can write in any programming language. All it does is output "Hello, World!" [3]

Writing our first program

"Hello, World!"

With our "php-intro-workshop" project there is a sample hello-world.php file

Variables

A variable is a storage location associated with a name.  Variables contain an unknown quantity or information called value [4]

<?php
// 01.simple_variable.php

$name = 'Juan';
$x = 30;
$y = 1.123;

// print the values below
print "";

Rules for PHP Variables [5]

• A variable starts with the $ sign, followed by the name of the variable.
• A variable name must start with a letter or the underscore character.
• A variable name cannot start with a number.
• A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )

Using PHP Variables [5]

<?php
// 02.hello_name.php

$name = 'Juan';
print "Hello, $name!";
/** 
 * This will output:
 * Hello, Juan!
 */

Data Types

A Data Type Is classification identifying one of various types of data [6]

Data Types

PHP Defines eight data types [7]

• Four scalar types:
  • boolean (true or false)
  • integer (negative & positive non factional numbers & zero)
  • float (floating-point number, aka double)
  • string  (a series of characters)
• Two compound types:
  • array (we'll try to cover arrays later)
  • object (we won't get to objects)
• And finally two special types:
  • resource (we won't get to resource)
  • NULL (variable with no value)

Data Types

<?php
// 03.data_types.php

print gettype(true)      . PHP_EOL;      // bolean
print gettype(12345)     . PHP_EOL;      // integer
print gettype(1.2345)    . PHP_EOL;      // double
print gettype("Hello")   . PHP_EOL;      // string
print gettype([1, 2, 3]) . PHP_EOL;      // array
print gettype(new stdClass()) . PHP_EOL; // object
print gettype(null)      . PHP_EOL;      // NULL

PHP_EOL is a constant that represents the "End Of Line" symbol.

Operators

An operator in a programming language is a symbol that tells the [computer] to perform specific mathematical, relational or logical operation and produce final result. [8]

An operator is something that takes one or more values (or expressions, in programming jargon) and yields another value. [9]

Arithmetic Operators

Assignment Operator

<?php
// 04.assignment_operator.php
$a = 1;
$b = 2;
$three = $a + $b;

print $three;

The assignment operator "=" is used to assign a value to a variable. It is not used to compare!

Comparison Operators

Comparison Operator

<?php
// 05.comparison_operators.php

var_dump(1 == 2);       // FALSE
var_dump(1 < 2);        // TRUE
var_dump(1 <= 2);       // TRUE
var_dump(2 > 2);        // FALSE
var_dump(2 >= 2);       // TRUE
var_dump(1 == true);    // TRUE - same as (bool)1 == TRUE
var_dump(1 === true);   // FALSE - same as (int)1 === FALSE
var_dump(0 == false);   // TRUE - same as (bool)0 == FALSE
var_dump(0 === false);  // FALSE - same as (int)0 === FALSE

The assignment operator "=" is used to assign a value to a variable. It is not used to compare!