A concise tutorial on array arrays and usages of PHP

  recently taught a friend PHP that he has no basis for other languages. The understanding and usage of array is somewhat vague. So write a tutorial, need a friend can refer to the next

Note The comments section of the text introduction Oh ~     Code as follows: <?php//Instantiate an array $array = array (); The array consists of two parts as follows//array (key name [key]=> value [value])//Key name General with index//type can be int or string [int is what can look up PHP manual]//So can write//$array = Array (0=&gt ;' A ',1=> ' B '); You can do the same.//array automatically supplements the index key name, which defaults to the int value starting at 0 $array = Array (' A ', ' B '); Test does not use Echo to print arrays only with Print_r   don't ask why, do it right print_r ($array); The output is  array ([0] => a [1] => B)//Can be seen, if you do not set the key name [key] It will automatically add key//You can also change the key $array = Array (3=> ' a ', 5 = > ' B '); Print_r ($array); Result Array ([3] => a [5] => B)//If you want to read the contents of the array, you can do echo $array [3]; The result is a //here with Echo because as long as it is not an array, it can be directly with echo output//key can be a string $array = Array (' AA ' => ' a ', ' BB ' => ' B '); Print_r ($array); The result is array ([AA] => a [BB] => B)//So you can also echo $array [' AA ']; Note that strings are enclosed in quotes/values [value] can be a variable, can be an array $array = Arrays (0=>array (' A ', ' B '), 1=>array (' C ', ' d ')); Print_r ($array); The result is array ([0] => Array ([0] => a [1] => B) [1] => Array ([0] => C [1] => D))//This is called two-dimensional array//read the contents of the inside Can be like this echo$array [0][1]; The result is that B can also be used  //Of course it can also include more array $array = Array (0=>array (' A ', ' B '), Array (' C ', ' d ')), 1=>array (' e ', '), " F '), Array (' G ', ' h ')); It looks a little messy, and you have to understand it. Returns to the actual application instantiate a number of rent $array = Array (); Simulating a SQL loop SQL is mostly done with the while loop, where I do a simple for 10 cycles   echo ' <br/> '; Echo ' <br/> '; For ($i =0 $i <=10; $i + +) {  $array [] = Array (' name ' => ' My Name '. $i, ' age ' => ' my 1 '. $i);   //$array []   Plus bracket is going to let him generate 10 arrays respectively 0-10  //if is $array = Array (' name ' => ' My name '. I, ' age ' => ' my aged 1 '. i);   //So result only There is an array. The last one will replace the previous one} print_r ($array); Result Array ([0] => Array ([name] => my name 0 [age] => my Ages) [1] => Array ([name] => my name 1 [age] => my ages one) [2] => Array ([name] => my Name 2 [age] => my old one) [3] => Array ([name] => my name 3 [age] => my ages 13) [4] => Array ([name] => my name 4 [age] => my old) [5] => Array ([name] => my name 5 [age] => my age) [6] => A Rray ([name] => my name 6 [age] => me) [7] => ARRAy ([name] => my name 7 [age] => my old) [8] => Array ([name] => my name 8 [age] => my age) [9] => array ([NA Me] => My name 9 [age] => my old) [a] => Array ([name] => my name [age] => my aged 110))//How to use it??>   ;ul>   <?php foreach ($array as $value) {  echo ' <li> '. $value [' name ']. '  |   '. $value [' Age '].' </li> '; }  ?> </ul>   <?php//above results added HTML code, you extrapolate it//if you want to operate the array, such as filtering the above $array a total of 10 arrays, now you want to delete the key 3 That one unset ($array [3]);  Print_r ($array); You'll see the  3. The above is a simple usage, next time say some advanced?>