Hướng dẫn dùng multidimensions trong PHP
What is a PHP Array?A PHP array is a variable that stores more than one piece of related data in a single variable. Think of an array as a box of chocolates with slots inside. The box represents the array itself while the spaces containing chocolates represent the values stored in the arrays. The diagram below illustrates the above syntax. Show Nội dung chính
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Numeric ArraysNumeric arrays use number as access keys. An access key is a reference to a memory slot in an array variable. The access key is used whenever we want to read or assign a new value an array element. Below is the syntax for creating numeric array in php. Array Example Or value, …); ?> HERE,
Let’s now look at an example of a numeric array. Suppose we have 5 movies that we want to store in array variables. We can use the example shown below to do that. Here, Output: Once upon a time in China Eastern Condors As you can see from the above examples, working with arrays in PHP when dealing with multiple values of the same nature is very easy and flexible. Alternatively, the above array variables can also be created using the following code. "Shaolin Monk", 1 => "Drunken Master", 2 => "American Ninja", 3 => "Once upon a time in China", 4 =>"Replacement Killers" ); echo $movie[4]; ?> Output: Replacement Killers Associative array differ from numeric array in the sense that associative arrays use descriptive names for id keys. Below is the syntax for creating associative array in php. value); ?> HERE,
Let’s suppose that we have a group of persons, and we want to assign the gender of each person against their names. We can use an associative array to do that.The code below helps us to do that. "Female", "John" => "Male", "Mirriam" => "Female"); print_r($persons); echo ""; echo "Mary is a " . $persons["Mary"]; ?> HERE, Output:Array ( [Mary] => Female [John] => Male [Mirriam] => Female ) Mary is a Female Associative array are also very useful when retrieving data from the database. The field names are used as id keys. PHP Multi-dimensional arraysThese are arrays that contain other nested arrays. The advantage of multidimensional arrays is that they allow us to group related data together. Let’s now look at a practical example that implements a php multidimensional array. The table below shows a list of movies by category.
The above information can be represented as a multidimensional array. The code below shows the implementation. array("Pink Panther", "John English", "See no evil hear no evil"), "action" => array("Die Hard", "Expendables"), "epic" => array("The Lord of the rings"), "Romance" => array("Romeo and Juliet") ); print_r($movies); ?> HERE, Output:Array ( [comedy] => Array ( [0] => Pink Panther [1] => John English [2] => See no evil hear no evil ) [action] => Array ( [0] => Die Hard [1] => Expendables ) [epic] => Array ( [0] => The Lord of the rings ) [Romance] => Array ( [0] => Romeo and Juliet ) ) Another way to define the same array is as follows array( 0 => "Pink Panther", 1 => "john English", 2 => "See no evil hear no evil" ), "action" => array ( 0 => "Die Hard", 1 => "Expendables" ), "epic" => array ( 0 => "The Lord of the rings" ), "Romance" => array ( 0 => "Romeo and Juliet" ) ); echo $film["comedy"][0]; ?> Output: Pink Panther Note: the movies numeric array has been nested inside the categories associative array PHP Arrays: Operators
PHP Array FunctionsCount functionThe count function is used to count the number of elements that an php array contains. The code below shows the implementation. Output: 3 is_array functionThe is_array function is used to determine if a variable is an array or not. Let’s now look at an example that implements the is_array functions. Output: 1 SortThis function is used to sort arrays by the values. If the values are alphanumeric, it sorts them in alphabetical order. If the values are numeric, it sorts them in ascending order. It removes the existing access keys and add new numeric keys. The output of this function is a numeric array "Female", "John" => "Male", "Mirriam" => "Female"); sort($persons); print_r($persons); ?> Output: Array ( [0] => Female [1] => Female [2] => Male ) ksortThis function is used to sort the array using the key. The following example illustrates its usage. "Female", "John" => "Male", "Mirriam" => "Female"); ksort($persons); print_r($persons); ?> Output: Array ( [John] => Male [Mary] => Female [Mirriam] => Female ) asortThis function is used to sort the array using the values. The following example illustrates its usage. "Female", "John" => "Male", "Mirriam" => "Female"); asort($persons); print_r($persons); ?> Output: Array ( [Mary] => Female [Mirriam] => Female [John] => Male ) Why use arrays?
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