1. Define an array.

$my_array = array();

2. Create a key for each string. You don't have to specify an index number (the number inside the brackets [ ] ) for each key, but I am doing so to make the flow better understandable.

$my_array[0] = "A";

$my_array[1] = "B";

$my_array[2] = "C";

$my_array[3] = "D";

$my_array[4] = "E";

$my_array[5] = "F";

$my_array[6] = "G";

$my_array[7] = "H";

$my_array[8] = "I";

$my_array[9] = "J";

$my_array[10] = "K";

$my_array[11] = "L";

$my_array[12] = "M";

$my_array[13] = "N";

$my_array[14] = "O";

$my_array[15] = "P";

$my_array[16] = "Q";

$my_array[17] = "R";

$my_array[18] = "S";

$my_array[19] = "T";

$my_array[20] = "U";

$my_array[21] = "V";

$my_array[22] = "W";

$my_array[23] = "X";

$my_array[24] = "Y";

$my_array[25] = "Z";

3. We need to store the highest index number (in this case '25') in a variable. This array has 26 items, but the highest index number is '25' because arrays start at '0'. So we count the size of the array using count($my_array), and then subtract '1' from it.

$array_size = count($my_array) - 1;

4. Now generate a random number between '0' (the lowest number in the array) and the value you've stored in the variable above. This will generate a random index number that matches an index number inside your array.

$random_index = mt_rand(0,$array_size);

5. Print the random key by putting the generated number above inside the brackets.

echo $my_array[$random_index];

The complete code:

// An array with some text.

// Modify it to contain the random texts it will show.

$my_array = array();

$my_array[0] = "A";

$my_array[1] = "B";

$my_array[2] = "C";

$my_array[3] = "D";

$my_array[4] = "E";

$my_array[5] = "F";

$my_array[6] = "G";

$my_array[7] = "H";

$my_array[8] = "I";

$my_array[9] = "J";

$my_array[10] = "K";

$my_array[11] = "L";

$my_array[12] = "M";

$my_array[13] = "N";

$my_array[14] = "O";

$my_array[15] = "P";

$my_array[16] = "Q";

$my_array[17] = "R";

$my_array[18] = "S";

$my_array[19] = "T";

$my_array[20] = "U";

$my_array[21] = "V";

$my_array[22] = "W";

$my_array[23] = "X";

$my_array[24] = "Y";

$my_array[25] = "Z";

// Get the size of the array for getting the highest index number.

// Arrays start at '0', so we subtract 1 from the total amount.

// Key number '26' will have an index of '25'

$array_size = count($my_array) - 1;

// Generate a number between 0 and the highest index number of the array

$random_index = mt_rand(0,$array_size);

// Print the array key with the generated index number

echo $my_array[$random_index];