What are the functions in php that convert strings to arrays?

PHP is a very popular programming language that has almost become a de facto standard in the field of web development due to its ease of learning and powerful functions. In PHP, string to array conversion is a basic operation that allows developers to convert a string into an array for better processing and manipulation of data. This article will introduce the use of string to array function in PHP.

1. String to array function in PHP

PHP provides many functions for converting strings to arrays. These functions use different syntax and parameters. The following are some commonly used methods:

1. explode() function:

explode() function can split a string into multiple substrings and return a string containing Array of substrings. This function accepts two parameters, the first parameter is the delimiter used to split the string, and the second parameter is the string that needs to be split.

Sample code:

$str = "apple, banana, cherry";
$arr = explode(",", $str);
print_r($arr);

Output result:

Array
(
    [0] => apple
    [1] => banana
    [2] => cherry
)

2. str_split() function:

This function splits a string Split into multiple characters and return an array containing those characters. Unlike the explode() function, str_split() does not require a separator to be specified.

Sample code:

$str = "apple";
$arr = str_split($str);
print_r($arr);

Output result:

Array
(
    [0] => a
    [1] => p
    [2] => p
    [3] => l
    [4] => e
)

3. preg_split() function:

This function allows the use of regular expressions to split the string and return an array. This function accepts two parameters, the first parameter is a regular expression pattern, and the second parameter is the string that needs to be split.

Sample code:

$str = "apple banana cherry";
$arr = preg_split("/[\s]+/", $str);
print_r($arr);

Output result:

Array
(
    [0] => apple
    [1] => banana
    [2] => cherry
)

2. Application of PHP string to array function

String The convert to array function is widely used in data processing and manipulation in PHP, especially when developers need to parse CSV files or other formats of text data. Here are some common application scenarios:

1. Parsing CSV files:

Sample code:

$file = fopen("data.csv", "r");
$data = array();

while(! feof($file))
  {
  $line = fgetcsv($file);
  $data[] = $line;
  }

fclose($file);
print_r($data);

2. Parsing URL query strings:

Sample code:

$query = "param1=value1&param2=value2&param3=value3";
parse_str($query, $params);
print_r($params);

Output result:

Array
(
    [param1] => value1
    [param2] => value2
    [param3] => value3
)

3. Convert string into numerical array

Sample code :

$str = "1,2,3,4,5";
$arr = explode(",", $str);
$array_map(function($val) {
  return (int) $val;
}, $arr);
print_r($arr);

Output result:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
)

Summary:

This article introduces common string to array functions in PHP, including explode(), str_split() and preg_split(), and explore the application scenarios of these functions. Understanding these functions and their purpose will allow developers to process and manipulate data more efficiently.

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