Lowercase:

strtolower($thirdString);

Uppercase:

strtoupper($thirdString);

Uppercase first-letter:

ucfirst($thirdString);

Uppercase words:

ucwords($thirdString);

Length:

strlen($thirdString);

Trim:

$fourthString = $firstString . trim($secondString);

Find:

strstr($thirdString, "brown");

Replace by string:

str_replace("quick", "super-fast", $thirdString);

Repeat:

str_repeat($thirdString,2);

Make substring:

substr($thirdString,5,10);

Find position:

strpos($thirdString,"brown");

Find character:

strchr($thirdString,"z");

Basic Math

((1 + 2 + $var1) * $var2) / 2 - 5;

$var1 = 3;

$var2 = 4;

+=:

$var2 += 4;

-=:

$var2 -= 4;

*=:

$var2 *= 3;

/=:

$var2 /= 4;

Increment:

$var2++; echo $var2;

Decrement:

$var2--; echo $var2;

Floating point:

$myFloat = 3.14;

Round:

round($myFloat, 1);

Ceiling:

ceil($myFloat);

Floor:

floor($myFloat);

Absolute Value:

abs(0-300);

Exponential:

pow(2,8);

Square root:

sqrt(100);

Modulo(/remainder):

fmod(20,7);

Random (any):

rand();

Random (min,max):

rand(1,10);

Single Dimensional Array

$array1 = array(4,6,8,16,32)

Reading

echo $array[0]

Multi-Dimensional Array

$array2 = array(4,6,8,array("X","Y","Z"),16,32)

Reading

echo $array[3][1]

Associative Array

$array("first_name"=>"Jeff", "last_name"=>"Davis")

Reading

echo $array3["first_name"]

Print Entire Array

print_r($array2)

Can use with html <pre></pre> tags

<pre><?php print_r($array2); ?></pre>

Count

count($array1)

Max Value

max($array1)

Min Value

min($array1)

Sort

sort($array1)

Reverse Sort

rsort($array1)

Implode(insert separators)

implode(" * ", $array1)

Explode(split at string)

explode(" * ", $string)

In array(bool)

in_array(3,$array1)

Switching from int to string

$var1 = "2 brown foxes", $var2 = $var1 + 3;

gettype

gettype($var1)

= string, integer, bool, array

settype

settype($var2, "string")

= string

is_array

is_bool

is_float

is_int

is_null

is_numeric

is_string