The essence of arrays: manages and operates a group of variables and processes them in batches. The following describes the array classification, array classification, and usage instructions.
Php Tutorial: Array declaration, traversal, array global variables
Value * Use "," to separate multiple members * 3. use other function declaration ***** // index array $ user [0] = 1; // user serial number $ user [1] = "zhangsan "; // username $ user [2] = 10; // Age $ user [3] = "nan"; // gender echo''; print_r($user); echo '
'; // Associated array $ user ["id"] = 1; $ user ["name"] = "zhangsan"; $ user ["age"] = 10; $ user ["sex"]; $ user ["age"] = 90; // value echo $ user ["name"]; // output // Use array () declare an array $ user = array (1, "zhangsan", 10, "nan"); // Use array () declare join array $ user = array ("id" => 1, "name" => "zhangsan", "age" => 10, "sex" => "nan"); // declare a multi-dimensional array (multiple records ), to save multiple user information records in a table $ user = array (// call this row with $ user [0], for example, call the name in this record, $ user [0] [1] array (1, "zhangsan", 10, "nan"), // call this line with $ user [1], such as calling this line Name in the record, $ user [1] [1] array (2, "lisi", 20, "nv"); // The array stores multiple tables, each table has multiple records $ info = array ("user" => array (1, "zhangsan", 10, "nan"), array (2, "lisi", 20, "nv"), "score" => array (,), array ))); echo $ info ["score"] [1] [1]; // output 60,?> Array Super global variable
"; Echo $ email ."
"; Echo $ page ."
"; // The most stable value method echo $ _ GET [" username "]."
"; Echo $ _ GET [" email "]."
"; Echo $ _ GET [" page "]."
";?> This is a $ _ GET test
'; Print_r ($ _ ENV); echo'
'; // Display the current environment. // Can a single traversal be performed?> "; Echo $ GLOABLS [" B "]."
"; Echo $ GLOABLS [" c "]."
";}?> Array traversal Value variable) {*} *** 3. while () list () each () combined loop traversal array ** each () function: * 1. an array is required as the parameter * 2. the returned result is an array * 3. the returned array is 0, 1, key, and value subscripts (fixed) * 0 and key subscript are the keys of the elements in the current parameter array * 1 and value subscript are the values of the elements in the current parameter array * 4. by default, the current element is the first element * 5. after each execution, the current element is moved backward * 6. if the last element executes this function again, false * list () function is returned: * 1. list () = array (); you need to assign an array to this function * 2. number of elements in the array, which must be the same as the number of parameters in the list () function * 3. each element value in the array is assigned a value to each parameter in the list () function, and list () converts each parameter to the variable * 4. list () can only accept index arrays * 5. assign a value to the parameter ***** in the subscript order of the index // for statement to traverse the array $ user = array (1, "zhangsan", 40, "nan "); for ($ I = 0; $ I <4; $ I ++) {echo "$ user [{$ I}] = ". $ user [$ I]."
";}// Use foreach $ user = array (1," zhangsan ", 40," nan "); foreach ($ user as $ val) // $ val is the custom variable {echo $ val."
"; // The output has nothing to do with the subscript} foreach ($ user as $ key => $ val) // $ val $ key is a custom variable {echo $ key. "====> ". $ val."
";}// Foreach traverse multi-dimensional arrays $ info = array (" user "=> array (// $ user [0] array (1," zansan ", 10, "nan"), // $ user [1] [1] array (2, "lisi", 20, "nv "), // $ user [1] // $ user [2] array (3, "wangwu", 30, "nan ")), "score" => array (1,100, 90, 80), array (2, 99, 88, 11), array (3, 10, 50, 88 )), "connect" => array (1, '000000', 'AAA @ bbb.com '), array (2, '000000', 'BBB @ ccc.com '), array (3, '20140901', 'CCC @ ddd.com '); foreach ($ info as $ tableName => $ table) {echo'
'; Echo'
'. $ TableName .'
'; Foreach ($ table as $ row) {echo'
'; Foreach ($ row as $ col) {echo'
| '. $ Col .' | ';} Echo'
';} Echo'
';} // Use of each () $ user = array ("id" => 1, "name" => "zhangsan", "age" => 10, "sex" => "nan"); $ a = each ($ user ); // Array ([1] => 1 [value] => 1 [0] => id [key] => id) the default value is print_r ($ a); $ B = each ($ user); print_r ($ B ); // Array ([1] => zhangsan [value] => zhangsan [0] => name [key] => name, traverse $ c = each ($ user); print_r ($ c ); // Array ([1] => 10 [value] => 10 [0] => age [key] => age) $ d = each ($ user ); print_r ($ d); // Array ([1] => nan [value] => nan [0] => sex [key] => sex) $ e = each ($ user); var_dump ($ e); // bool (false) value returned when no element exists // each () with while traversal $ user = array ("id" => 1, "name" => "zhangsan", "age" => 10, "sex" => "nan"); while ($ arr = each ($ user) {// echo $ arr [0]. "===> ". $ arr [1]."
"; // Display the key (subscript) and value echo $ arr [" key "]." => ". $ arr [" value "]."
"; // Use key and value to display key values} // use list ($ name, $ age, $ sex) = array (" zhangsan ", 10, "nnnnn"); echo $ name."
"; Echo $ age ."
"; Echo $ sex ."
"; // Another method to use list (, $ sex) = array (" zhangsan ", 10," nnnnn "); echo $ sex ."
"; // Only convert gender to variable // ip judge $ ip =" 192.168.1.128 "; list (, $ d) = explode (". ", $ ip); // explode is used. returns an array echo $ d; // retrieves 128 // list () can only receive the example of an index array $ user = array ("id" => 1, "name" => "zhangsan", "age" => 10, "sex" => "nan"); list ($ key, $ value) = each ($ user); // Array ([1] => 1 [0] => id) assigns values to parameters in the list according to the order in which the index falls, so first the 0 key and then the 1 value echo $ key. "---> ". $ value; // while list () each () use $ user = array ("id" => 1, "name" => "zhangsan ", "age" => 10, "sex" => "nan"); while (list ($ key, $ value) = each ($ user) {echo $ key. "---> ". $ value."
";}// The solution for displaying only one loop for multiple times // use the internal pointer control function of the array // next (array ); the array pointer moves to the next // prev (array); the array pointer moves to the previous // reset (array); the array pointer moves to the first (reset) // end (array ); the array pointer moves to the last // current (array); obtains the value of the current element, and the element pointed to by the index group pointer when the current element. // Key (array); obtain the key value (subscript) of the current element $ user = array ("id" => 1, "name" => "zhangsan ", "age" => 10, "sex" => "nan"); while (list ($ key, $ value) = each ($ user) {echo $ key. "---> ". $ value."
";}/// Move the array pointer here to the first loop below to output // reset ($ user) while (list ($ key, $ value) = each ($ user) // because each () returns false to the last one, the loop jumps out of {echo $ key. "---> ". $ value."
";} While (list ($ key, $ value) = each ($ user) // because each () returns false to the last one, so the loop jumps out of {echo $ key. "---> ". $ value."
";} Echo current ($ user)." ===> ". key ($ user);?>
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