Functions in PHP8: Efficient string search techniques for str_contains()

Functions in PHP8: Efficient string search techniques for str_contains()

With the release of PHP8, we have more new features and improvements, one of the most noteworthy new features is str_contains() function. This function can be used to determine whether a string contains another string. In this article, we will take a deep dive into the str_contains() function and its usage in PHP, and how to use it for efficient string searches.

Disadvantages of conventional methods

In the past, to find a specific substring in a string, we usually used the strpos() function. This function searches a string within another string and returns the first position found. For example, find the first occurrence of "hello" in the string:

$string = 'hello world';
$position = strpos($string, 'hello');

However, the strpos() function has a flaw, that is, it will stop after searching for the first matching substring. . If we want to find all matching substrings in a string, we must use a loop to search for each matching substring:

$string = 'hello world';
$needle = 'l';
$offset = 0;
$positions = array();
while (($position = strpos($string, $needle, $offset)) !== false) {
    $positions[] = $position;
    $offset = $position + 1;
}

Although this method works, the code is a bit verbose , and the search speed is also slower. In this case, the str_contains() function will obviously be more efficient.

str_contains() function

The str_contains() function is a new function added in PHP8. It can quickly determine whether a string contains another string. This function only needs to pass two parameters: the string to be searched and the substring to be searched. It returns a Boolean value indicating whether a matching substring was found in the string being searched. Here is a simple example:

$string = 'hello world';
$needle = 'hello';
$is_contains = str_contains($string, $needle);

In this example, the value of $is_contains will be true. If we call this function again but set the $needle variable to "goodbye", the value of $is_contains will be false.

Internally, the str_contains() function uses a more efficient algorithm to find substrings. Compared with the strpos() function, it is more efficient and the code is simpler.

Improve search efficiency

Although the str_contains() function itself is very efficient, there are some techniques that can help us further improve search efficiency. Here are some tips:

1. Don’t search repeatedly

If we need to search a string multiple times, then we should avoid searching the string repeatedly. Instead, we should search the string once and store the results in a variable. We can then use this variable to determine if a string contains a certain substring without having to search again every time.

2. Reduce the scope of the search as much as possible

If we need to search for a substring in a long string, then we can narrow the scope of the search as much as possible. For example, we can use the substr() function to intercept a part of the original string and then search for this substring. This can greatly reduce the time complexity.

3. Avoid using the str_contains() function in a loop

Although the str_contains() function is very efficient, using it in a loop may slow down the search. If we need to search multiple substrings in a loop, then we should first store these substrings in an array and then call the str_contains() function outside the loop. This avoids repeated function calls and greatly speeds up searches.

Conclusion

The str_contains() function is a very useful new function in PHP8. It can help us quickly determine whether a string contains another string. It is more efficient than conventional methods and the code is cleaner. Although it is already very efficient, we can still use some tricks to improve search efficiency. Whether you are searching for a large string or multiple substrings, using the str_contains() function is a very good choice.

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