Sharing of efficient php writing methods

This article mainly shares with you how to write efficient PHP, hoping to help everyone.

1. Static static

Static variables start with the creation of the class and end with the death of the class; non-static variables start with the creation of the class instance and end with the death of the class instance. Static methods can be called directly, while instance methods must be called through instances, and static methods are much faster. Static methods always call the same memory and cannot be automatically destroyed, but can be destroyed by instantiation.

2. Echo is more efficient than print

Because echo does not return a value, while print returns an integer. Note that when echoing a large string, performance will be seriously affected if no adjustments are made. Use mod_deflate to open apached for compression or open ob_start to put the content into the buffer first.

3. Set the maximum number of times before looping, not during the loop;

For example, it is calculated every time in the for loop.

4. Destroy variables to release memory, especially large arrays;

Arrays and objects are special in PHP Memory usage is due to the underlying zend engine of PHP. Generally speaking, the memory utilization of PHP arrays is only 1/10. In other words, an array with 100M of memory in C language will cost 1G in PHP. . Especially in systems where PHP is used as a backend server, the problem of excessive memory consumption often occurs.

5. requiere_once() consumes more resources;

This is because requiere_once requires Determine whether the file has been referenced, so try not to use it if possible. Commonly used require/include methods to avoid.

6. Use absolute paths in includes and requires.

#If a relative path is included, PHP will traverse the include_path to find the file. Using absolute paths will avoid such problems, so it will take less time to resolve the operating system path.

7. Can use PHP’s internal string manipulation functions In this case, try to use them instead of regular expressions; because its efficiency is higher than regular expressions;

str_replace character replacement is faster than regular replacement preg_replace, but strtr is 1/4 faster than str_replace ;

Also don’t do unnecessary substitutions. Even if there is no substitution, str_replace will allocate memory for its parameters. very slow! Solution: Use strpos to search first (very fast) to see if replacement is needed, and then replace if necessary. Efficiency: - If replacement is required: Efficiency is almost equal, the difference is around 0.1%. If no substitution is required: using strpos is 200% faster.

##8. It is best not to use @, using @ to cover up errors will reduce the running speed of the script;

Using @ actually has many operations in the background. The efficiency difference between using @ and not using @ is: 3 times. Especially do not use @ in a loop. In the test of 5 loops, even if you use error_reporting(0) to turn off the error first and then turn it on after the loop is completed, it is faster than using @.

9.$row['id'] is 7 times faster than $row[id]; It is recommended to develop the habit of adding quotes to array keys;

10.Don’t use functions in loops

##For example, For($x=0; $x < count($array); $x), the count() function calculates first outside;

11. Creating an undeclared local variable is 9-10 times slower than an already defined local variable

12.

Single quotes instead of double quotes to contain strings

13.

Apache parses a PHP The script is 2 to 10 times slower than parsing a static HTML page.

Try to use more static HTML pages and less scripts.

14. Don’t just copy variables

Sometimes in order to make the PHP code neater, some PHP newbies (including me) will copy the predefined variables into a variable with a shorter name. In fact, the result of this is doubling the memory consumption, which will only make the program slower.

15. Use the selective branch statement

switch case is better than using multiple if, else if statements, and the code is easier to read and maintain.

16. Try to do as few file operations as possible, although PHP’s file operation efficiency is not low;

You can use file_get_contents instead of file, fopen, feof, fgets

17. Use PHP internals as much as possible Function

18. foreach is more efficient, try to use foreach instead of while and for loop;

##19. Do not declare variables inside the loop, especially large variables: objects

20. For global variables, you should unset() them after use;

21. Using ++$i to increment

$i++ will be slower than ++$i. This difference is specific to PHP and does not apply to other languages. Post-increment actually creates a temporary variable that is subsequently incremented. Prefix increment increases directly on the original value. This is a form of optimization, as done by Zend's PHP optimizer.

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