Chapter III using Arrays (2)

• Multidimensional arrays

　　　Two-dimensional arrays: equivalent to 1 matrices, or a grid with width and height or rows and columns. For example: This figure holds Bob's product in a two-dimensional array, each line represents a product,

Each column represents the product's attributes (Products attribute).

PHP Code implementation:

//create a two-dimensional array$products 2=Array(Array(' TIR ', ' Tires ', 100),Array(' oil ', ' oil ', 10),Array(' SPK ', ' Spark plugs ', 4));//Show this array in the browserEcho' | '.$products 2[0] [0]. ' | '.$products 2[0] [1]. ' | '.$products 2[0] [2]. " <br/> ";Echo' | '.$products 2[1] [0]. ' | '.$products 2[1] [1]. ' | '.$products 2[1] [2]. " <br/> ";Echo' | '.$products 2[2] [0]. ' | '.$products 2[2] [1]. ' | '.$products 2[2] [2]. " <br/> ";

Example effect:

You can also use a double for loop to achieve the same effect:

 for ($row = 0; $row < 3; $row+ +)    {for ($column = 0;  $column < 3; $column+ +)        {echo "|". $products 2 [$row] [$column];    }     Echo "<br/>";}

　　　　　　　　　Another implementation of the PHP code (creating a column name instead of a number)-(descriptive index):

//create a two-dimensional array$products 3=Array(Array(' Code ' = ' TIR ', ' Description ' = ' Tires ', ' Price ' =>100),Array(' Code ' = ' oil ', ' Description ' = ' oil ', ' price ' =>10),Array(' Code ' = ' SPK ', ' Description ' = ' Spark plugs ', ' price ' =>4));//Show this array in the browser for($row= 0;$row< 3;$row++){    Echo"|".$products 3[$row[' Code ']. "|".$products 3[$row[' Description ']. "|".$products 3[$row[' Price ']. " <br/> ";}

The example shows the same effect as the previous example.

You can also use the each () and list () functions to traverse the entire inner array in a while loop:

 // show this array in the browser  Span style= "color: #0000ff;" >for  ( $row  = 0; $row  < 3;  $row  ++) {  (list  ( $key ,  $value ) =each  ( $products 3  [ Span style= "color: #800080;" > $row   echo  "| $value  ";  echo  "<br/>" ;}  

If Bob wants to classify his product: Car,van, Truck, use a three-dimensional array:

//create a three-dimensional array$categories=Array(Array(Array(' Car_tir ', ' Tires ', 100),Array(' Car_oil ', ' oil ', 10),Array(' CAR_SPK ', ' Spark plugs ', 4)                            ),Array(Array(' Van_tir ', ' Tires ', 100),Array(' Van_oil ', ' oil ', 10),Array(' VAN_SPK ', ' Spark plugs ', 4)                            ),Array(Array(' Trk_tir ', ' Tires ', 100),Array(' Trk_oil ', ' oil ', 10),Array(' TRK_SPK ', ' Spark plugs ', 4)                        )                    );//Show this array in the browser for($layer= 0;$layer< 3;$layer++){    EchoThe Layer$layer<br/> ";  for($row= 0;$row< 3;$row++){         for($column= 0;$column< 3;$column++){            Echo"|".$categories[$layer][$row][$column]; }        Echo"<br/>"; }}

And so on, you can create four-dimensional, five-D, or six-dimensional arrays.

• Array sorting

　　　　Use the sort () function:

$products 4 Array (' Tires ', ' oil ', ' Spark plugs '); Sort ($products 4);

Now the product order becomes: oil, Spark plugs, Tires

Note: the sort () function is case-sensitive and all uppercase letters precede lowercase letters, for example:

$products 4 Array (' Tires ', ' oil ', ' Spark plugs '); Sort ($products 4);  for ($row = 0; $row < 3; $row+ +)    {echo$products 4[$row]. " ";}

The results shown are:

　　　　Use the Asort () function and the Ksort () function to sort the associative array: If you store individual items and their prices with associative arrays, you need to use different sort functions to keep the keywords and values consistent when sorting.

The following code creates an array of 3 products and prices, and then sorts them in ascending order of prices:

$products 5 Array (' Tires ' =>100, ' oil ' =>10, ' Spark plugs ' =>4); Asort ($products 5); foreach ($products 5as$key$val) {    echo '$key $val<br/> ";}

Note that the asort is to be traversed with foreach, with the result:

Use Ksort to sort:

$products 6 Array (' Tires ' =>100, ' oil ' =>10, ' Spark plugs ' =>4); Ksort ($products 6); foreach ($products 6as$key$val) {    echo '$key $val<br/> ";}

The example results are:

In addition, the sort ()/asort ()/ksort () each corresponds to a reverse sort function: Rsort (), Arsort (), Krsort ().

Chapter III using Arrays (2)