Php practical functions, php function _ PHP Tutorial

Php practical functions: php functions. Php practical functions: for the first time, write some practical functions in your work. Array Function: 1array_column -- return the specified column in the array. usage 1: php return function, php function

For the first time, write some useful functions in your work.

Array functions:

1 array_column -- return the specified column in the array

Usage 1: return a column specified in the array

Application scenario: retrieve the id of the class and query other information of the class from other tables.

Benefit: reduce the number of times the database is queried (all information is retrieved at one time by id)

Column:

　　　　

$ Records = array (
Array (
'Id' => 2135,
'First _ name' => 'John ',
'Last _ name' => 'Doe ',
),
Array (
'Id' => 3245,
'First _ name' => 'Sally ',
'Last _ name' => 'Smith ',
)
);

$ First_names = array_column ($ records, 'id ');
Print_r ($ first_names );

// Result

Array ('20140901', '20140901 ');

?>

Usage 2: use the id in a two-dimensional array as the key of the array

Application scenario: Retrieve data using array ['id ']

Benefit: use array_column instead of foreach to use the id in the two-dimensional array as the key of the array. the code is concise and calls system functions to improve efficiency.

Column:

　　　　

$ Records = array (
Array (
'Id' => 2135,
'First _ name' => 'John ',
'Last _ name' => 'Doe ',
),
Array (
'Id' => 3245,
'First _ name' => 'Sally ',
'Last _ name' => 'Smith ',
)
);

// Use foreach

$ Records_key = array ();

Foreach ($ records as $ k => $ v ){

$ Records_key [$ v ['id'] = $ v;

}

Print_r ($ first_names );
// Call array_column
$ Records_key = array_column ($ records, NULL, 'id ');
Print_r ($ first_names );

?>

// Result

Array (

[2135] => Array (
[Id] = & gt; 2135
[First_name] => John
[Last_name] => Doe
)

[3245] => Array (
[Id] = & gt; 3245
[First_name] => Sally
[Last_name] => Smith
)

)

　　　　

2 array_multisort -- sorts multiple arrays or multi-dimensional arrays

Usage 1: multi-dimensional array sorting

Application scenario: sort data by Price in descending order and by sales volume in ascending order

Benefits:

Column:

　　　　 $ Data [] = array ('price' => 67, 'Sale _ num' => 2 );
$ Data [] = array ('price' => 86, 'Sale _ num' => 1 );
$ Data [] = array ('price' => 85, 'Sale _ num' => 6 );
$ Data [] = array ('price' => 98, 'Sale _ num' => 2 );
$ Data [] = array ('price' => 86, 'Sale _ num' => 6 );
$ Data [] = array ('price' => 67, 'Sale _ num' => 7 );

// Retrieve the column list

$ Price = array_column ($ data, 'price ');

$ Sale_num = array_column ($ data, 'Sale _ num ');

// Use $ data as the last parameter and sort it by a common key

Array_multisort ($ price, SORT_DESC, $ sale_num, SORT_ASC, $ data );
?>

// Result　

　　　　 price | sale_num　　　　-------+--------  　　　　  98 |       2 　　　　   86 |       1　　　　    86 |       6　　　　    85 |       6　　　　    67 |       2  　　　　  67 |       7

Not complete to be continued!

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