PHP functions, arrays, strings and objects
Functions, arrays, strings and objects in PHP are the four most commonly used data types in development. Let’s talk about it briefly today PHPFunction, array, string object. In PHP development, this data type must be known.
Function
PHP functions are actually the same as JS functions
Use function to define a new function, followed by the name of the function. Then there is the function code
But you can use var in JS to define an anonymous function, but PHP cannot do this
The parameters passed in the PHP function are all You need to add the $ prefix, and you can't add anything like JS. Among the default values of parameters, PHP directly assigns the default value to the parameter in () of the positioning parameter. This is still the same as JS. The same
One difference between PHP and JS is that PHP can use & to pass references
In fact, this is also very simple, just use parameters to pass in the variables of the code, the code As follows:
functiondisplay(&$text) {
$text .= "say hello.;
}
$my ="good, "
display($my)
echo $my//good, say hello.Another thing is different from JS, but the same thing as Python is that include and require
Generally there is only one global scope in JS, so for different JS files , it is difficult to communicate (also because communication between JS is generally achieved through different js files with different scripts in HTML, but due to the existence of same-origin security restrictions, it is difficult for js to communicate between different files) )
But PHP, like python, can easily communicate with different files. Python uses import
, while PHP has two types, one is include and the other is require. The effect is also very obvious. include refers to inclusion, that is, the code can be run regardless of whether it is included or not, but require must contain the require code to run the subsequent code
StringIt’s the same as JS, you need to escape \\, or it’s a built-in function for string operations
, the idea is the same, when you need to use these functions Let’s look for itPHP arrays are the same as JS arrays. The types of array elements can also be inconsistent, and each element can be used array[index] to get
. But when creating an array, PHP is different from JS. When using index to create an array, you can use the following method to create $myArray = array(0=>1, 1=>2, 2=>3). There is no need to add a new in front of the array here like JS. In (), index is used to create elements. What is used is =>, which is not available in JS.array_splice
The function can delete elements in the arrayarray_solice($myArray, 4) The first parameter is the array, and the second parameter is index.
Array traversal
, the one used in JS is , while the one used in PHP is foreach($myArrayas $key => $value) It can also be foreach($myArrayas $value)Of course it is still a function that operates on the array, this part is omittedObject
Like most languages, PHP also includes classes, objects, polymorphism, methods, properties, inheritance and encapsulation
$this->Variable name
To reference the relevant attributes of the internally visible classThe default is public public can be set to private private or protectedThe get and set accessors are the same as those of JSThe above is all the content of this article. I hope it will be helpful to new PHP programmers~Related recommendations:
The basic structure of PHP functions
The most complete introduction to PHP arrays
The most complete PHP string processing function
PHP object instantiation singleton method
The above is the detailed content of PHP functions, arrays, strings and objects. For more information, please follow other related articles on the PHP Chinese website!
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