# PHP

## Running

See setup and AMP notes, need the server

## Basics

```php
<?php
  //code here
  $my_name = "JJ";
  print($my_name);
    print "Hi"
?>
<div> body </div>
```

* dynamically typed language
* All **variable** names begin with a `$` followed by letters digits or underscores

### Printing

* echo //no return type
* print //return true always
* if you use (), only one argument
* should do `$s." ".$t`

### Functions

* Function names are not case sensitive
* & in function def is pass by reference
* javascript scoping for functions not {}
*   global declaration `global $x` makes it Avaliable everywhere

    ```php
    <?php
    function increment(&$num) {
    // this $num is the actual parameter below
    $num++;
      print('$num in function: ' . "$num");
    }
    ?>
    ```

### Strings

```php
<?php 
  "Passwd:$password[Joe]" #double quotes allow interpolation
  $name = 'j' . 'f' #concatination
  $str = implode("^",$ar") #join in python
  $ar = explode(":",$str); #split in python
?>
```

### Arrays

Basically dictionaries that if not set use numeric indexes

```php
<?php
$ar = array("key1"=>"value 1", 67=>3, "a"=>10, 4=>"Hi");
$x = array();
$my_array[2] = 2006; // this is literally declaring an array
$my_array = array("Hello",2,TRUE);

$usernames = array_keys($ar);
$passwds= array_values($ar);
?>
```

_Functions to call on arrays_

* unset //entry or entire array
* count OR sizeof
* is\_array

### Control

*   if and then like C++, switch statement

    **Loops**
* while, for

```php
<?php
  foreach($array as $value) {}
  foreach($array as $key => $value){}
  for ($i = 0; $i < 10; $i++) {
    //
  }
?>
```

### Big Project Functions

* isset($x)
* gettype($x)

## Includes

`include("filename")`

* check

## ERRORS

Do not put a space between #!/usr/local/bin/php \<?php ?>
