General

• W3Schools.
• PHP The Right Way.
• Learn PHP.
• Zend’s PHP 101.
• Learn X in Y Minutes: PHP.

Tools

• phpDocumentor.
• EasyPHP – To setup a local WAMP server.
• Laravel – PHP framework.
• CodeIgniter – PHP framework.
• PHPUnit – For unit testing.

News

• Reddit.

See Also

• Hack – A version of PHP written by Facebook.
• HHVM – A PHP server meant to run Hack apps.

Know This

• PHP code goes between delimiters: <?php and ?>
• Output string: echo “My string”;
• Concatenation: . (e.g. “Hello” . “!” gives “Hello!”)
• All variables in PHP start with a $
• Add a semicolon at the end of each statement.
• x++ is shorthand for x+1
• Comments: // or multi-line:  /* */
• Comparison Operators:
  • >
  • <
  • <=
  • >= Greater than or equal to
  • == Equal to
  • != Not equal to
• Conditional Statement:
  • If:
    • If (condition) { statement; }
  • Else:
    • If (condition) { statement; } else { statement; }
  • Else If:
    • If (condition) { statement; } elseif (condition) { statement } else { statement }
  • Switch:
    • switch (variable) { case 1: statement; break; case 2: statement; break; default: statement; }
• Arrays
  • $array = array(“Blue”, “Orange”, “Green”);
  • Each item in an array is numbered, starting on the left with 0.
  • Use brackets to access an item at a specific position in an array, e.g. $array[1]
    • Alternatively one can use {}. e.g. $array{1}
  • To set an element in an array: $array[1] = newvalue
  • To remove an element from an array use unset: unset($array[1]).
• Loops
  • For
    • for (start_of_loop; end_of_loop; increment_loop)
    • ex.: for (x=1; x<10; x++) { command; }
  • While
    • while (condition) { code }
    • ex.: while (x < 10) { x++; }
    • Alternatively, one can use while (cond): code endwhile;
  • Do While
    • Will execute at least once
    • do { code } while (condition);
    • ex.: do { x+1 } while (x < 1);
  • Foreach
    • foreach (list_of_items as item) { code }
    • foreach ($numbers as $item)  { echo $item; }

Functions

• array-merge()
• array_shift() – Takes the first value in an array out of the array and returns it.
• defined() – Checks whether a given constant exists.
• explode() – Used to create an array from a string.
• mt_rand() – Uses Mersenne Twister (mt_) to more quickly generate a random number.
• strlen()
• str_replace() – Replaces matching values found in a string with a given value.
  • str_ireplace() is case-insensitive.
• Why are there leading underscores in some function names?

Operators

• ? – ternary (aka conditional) operator
  • ex.: $param=isset($_GET[‘param’]) ? $_GET[‘param’] : ‘default’;
  • If the first parameter is true, use its result; otherwise if second is true; use its result; else use third.
  • Leaving out middle operand is supported in PHP 5.3+, middle operand above is “$_GET[‘param’]. Without middle operand looks like: $result = $x ?: ‘default’;
• :: – scope resolution (aka paamayim nekudotayim) operator
  • Used when one wants to reference a specific instance of a function.

Terms

• static
• scope resolution operator

Old Code

• &$this – See Tom J. Nowell’s article of the same name. Also this and this question on Stackoverflow.

Further Reading

• Stackoverflow
  • When to use self vs. $this?