'php and mysql web development' notes - Chapter 3 Using arrays

You can use = to copy an array into another array.

range(): used to generate an arithmetic sequence array.

asort(), arsort(): value sorting

$arr[0]=”hello”;//Directly create an array with a length of 1, which is equivalent to $arr = array(“0”=>”hello”);

$arr[1]=”world”;

$arr2 = array(“hello”,”world”);//Equivalent to the above two lines of code

foreach($arr as $ now)//foreach loop

{

             echo $now."
";

}

foreach($arr as $key=& gt;$ value)

{

echo $key.":".$value."
";

}

reset($arr);//Reset pointer

//each function

while($element=each($arr))

{

                          echo $element['key'].":".$element[ 'value']."1
";

}

//Use list to loop

reset($arr);

while(list($key . $arr1+$arr2: Add the latter element to the back of the former. The same key will not be added or overwritten.

Array sorting:

sort(), rsort(): ascending order, descending order

ksort(), krsort( ): Key sorting

usort(), uasort(), uksort(): Custom comparison rules, custom comparison functions are required

Other operations on arrays:

current(): Return the current pointer element, alias pos()

reset(), end(): pointer points to the beginning and end

next(), prev(): remove the next/previous element

shuffle() : Random elements, will modify the original array

                                                    use using a user’s own function ’ s ‐ ‐     ‐   ‐ ‐ ‐ being in reverse order,

) Count (), sizeof (): Calculate array length

Array_Count_values ​​(): Statistically frequency of value

Extract ()

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