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This article mainly introduces how to use SPL in PHP, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

The details are as follows:

I was so impressed by the above article on Rafael Dohms that I couldn't help translating it and adding some of it at the same time.

SPL,PHP Standard Library (Standard PHP Library), built-in components and interfaces since PHP 5. 0, and gradually matured from PHP5.3. SPL is actually built into all PHP5 development environments without any settings.

It seems that many PHP developers barely use it, or even have never heard of it. The reason can be traced back to its snowy documentation, which makes you ignore "its existence". The gem SPL was sunk to the bottom of the sea like Titanic's "heart of the sea". And now it should be picked up by us and put on where it should be, and this is the point of this article.

So, what does SPL offer?

SPL extends the PHP engine, such as ArrayAccess, Countable, and SeekableIterator interfaces, which are used to manipulate objects as arrays. At the same time, you can also use RecursiveIterator, ArrayObejcts and other iterators to iterate over the data.

It also has several built-in objects such as Exceptions, SplObserver, Spltorage and helper functions (helper functions) of splautoloadregister, splclasses, iteratorapply, etc., which are used to overload the corresponding functions.

Taken together, these tools are like multi-functional Swiss Army knives, and making good use of them can qualitatively improve the code efficiency of PHP. So, how do we exert its power?

Overload autoloader

If you're a textbook programmer, make sure you know how to use _ _ autoload instead of includes/requires to lazily load the corresponding classes, right?

But for a long time, you will find that you are already in trouble. The first thing is to make sure that your class file must be in the specified file path. For example, in the Zend framework, you must use "_" to split the class and method name (how do you solve this problem? ).

Another problem is that as the project becomes more and more complex, so does the logic in _ _ autoload. In the end, you will even add exception judgment and write all the logic of the loaded class into it.

As we all know, "eggs can't be put in one basket". Using SPL, you can separate the loading logic of _ _ autoload. Just write your own autoload function and overload it using the functions provided by SPL.

For example, with the problem with the Zend framework above, you can overload the method corresponding to Zend loader, and if it does not find the corresponding class, then use the function you defined earlier.

As you can see, spl_autoload_register can also add multiple loading logic in the form of arrays. At the same time, you can also use spl_autoload_unregister to remove load logic that is no longer needed, which will always be used.

Iterator

Iteration is one of the common design patterns, which is widely used in the unified traversal operation in a set of data. It is no exaggeration to say that SPL provides iterators of all the corresponding data types you need.

A very good example is traversing directories. The general practice is to use scandir, and then skip "." and "..", as well as other files that do not meet the criteria. For example, if you need to traverse a directory to extract image files from it, you need to determine whether it ends with jpg or gif.

The following code is an example of using SPL's iterator to perform the above recursion to find the picture file in the specified directory:

You might say, doesn't it take more code to do the same thing? So, if you look at the code above, don't you have code that is highly reusable and testable:)

Here are the other iterators provided by SPL:

RecursiveIterator

RecursiveIteratorIterator

OuterIterator

IteratorIterator

FilterIterator

RecursiveFilterIterator

ParentIterator

SeekableIterator

LimitIterator

GlobIterator

CachingIterator

RecursiveCachingIterator

NoRewindIterator

AppendIterator

RecursiveIteratorIterator

InfiniteIterator

RegexIterator

RecursiveRegexIterator

EmptyIterator

RecursiveTreeIterator

ArrayIterator

Starting with PHP5.3, there will be more iterators built in, and I think you can try them all. Maybe it will change your habit of writing traditional code.

SplFixedArray

SPL also comes with a series of array manipulation tools, such as the ability to instantiate a fixed-length array using SplFixedArray. So why use it? Because it's faster, even it's related to your salary:)

We know that PHP's regular array contains different types of keys, such as numbers, strings, and so on, and the length is variable. Because of these "advanced features", PHP gets the corresponding values through keys in a hash way-- which can cause performance problems in certain cases.

SplFixedArray does not use hash storage because it uses fixed numeric keys. Not exactly, you can even think of it as a C array. This is why SplFixedArray is faster than normal arrays (only in PHP5.3).

How fast is that? the following set of data can give you a glimpse into it.

If you need a lot of array operations, then you can try and believe that it is trustworthy.

Data structure

At the same time, SPL also provides some implementation of basic types of data structures. Although we can use traditional variable types to describe data structures, such as arrays to describe stacks (Strack)-- and then use the corresponding ways pop and push (arraypop (), arraypush ()), you have to be careful, because, after all, they are not specifically used to describe data structures-a single misoperation can break the stack.

The SplStack object of SPL strictly describes the data in the form of stack and provides corresponding methods. At the same time, such code should also be able to understand that it is manipulating the stack rather than an array, so that your partner can better understand the corresponding code, and it is faster.

Finally, the above pale examples may not be enough to "tempt you" to use SPL. Practice comes out of true knowledge, more and more powerful functions of SPL need to be explored by yourself. And it is carved slowly like a gem to give off brilliance.

Thank you for reading this article carefully. I hope the article "how to use SPL in PHP" shared by the editor will be helpful to everyone. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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