A deep dive into some often overlooked PHP functions

php is a very popular programming language due to its wide applicability in website and application development. Although PHP provides many functions to handle various tasks, there are actually many hidden functions. These functions are less common, but if you know them, they can be of great help. In this article, we will take a deep dive into some PHP functions that people often overlook.

1. array_column

The array_column function is a very useful function that can retrieve the value of a single column from a multidimensional array. It accepts three parameters: associative array or index array, column name or column index, and the last optional parameter is $index_key. This function greatly simplifies the process of extracting data from two-dimensional arrays for developers. The following is a sample code:

$users = [
  ['id' => 1, 'name' => 'John', 'email' => 'john@example.com'],
  ['id' => 2, 'name' => 'David', 'email' => 'david@example.com'],
  ['id' => 3, 'name' => 'Robert', 'email' => 'robert@example.com'],
];

// 获取所有用户的姓名列
$names = array_column($users, 'name');
// 输出结果 Array ( [0] => John [1] => David [2] => Robert )

2. substr_replace

The substr_replace function can be used to replace part of the string. It can support replacement starting from any position in the string and replacing characters of a specified length. . This function can be very useful when processing many string operations. Here is a sample code:

$str = 'hello world';
$result = substr_replace($str, 'friend', 6, 5);
// 输出结果 hello friend

3. scandir

The scandir function is used to read and return all files and subtitles in the specified directory. Directory, returned as an array. This function is very useful and allows you to quickly get all the file and directory names in a directory. Here is a sample code:

$path = '/path/to/directory';
$files = scandir($path);
// 输出结果 Array ( [0] => . [1] => .. [2] => file1.txt [3] => file2.txt [4] => subdir )

4. strtok

The strtok function can break a string into words or tokens, returning each token while maintaining an internal pointer to keep track of its position. This function is typically used to read data from text files or csv files.

Here is a sample code that reads a comma separated string and breaks it into individual words:

$string = "apple, orange, banana, pear";
$token = strtok($string, ",");
while ($token !== false) {
  echo $token . "<br>";
  $token = strtok(",");
}

// 输出结果：
// apple
//  orange
//  banana
//  pear

5. parse_str

parse_str function You can parse the query string into variables and values ​​from the string, save it in an array and return the array. This function is great for handling url query parameters. The following is a sample code:

$query = "name=John&age=30&gender=male";
parse_str($query, $output);
// 输出结果 Array ( [name] => John [age] => 30 [gender] => male )

6. file

The file function can read the entire file content in the form of an array, and each element is a line of the file. This function is very useful for quickly reading file contents and processing them. The following is a sample code:

$file_lines = file("/path/to/file.txt");
// 输出结果 Array ( [0] => line 1 [1] => line 2 [2] => line 3 )

Conclusion

The above are some less common but very useful php functions. I hope this article will be helpful to you and allow you to better master the php programming language. . There are many similar hidden functions, and we encourage you to learn and try to use them to fully realize the potential of PHP.

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