How to use specified symbols to split strings and convert them into arrays in PHP

Two implementation methods: 1. Use the explode() function to split the string using the specified symbol as the delimiter and convert it into an array. The syntax is "explode("specified symbol",$str)"; 2. Use the preg_split() function to split the string by matching the specified character with a regular expression and convert it into an array. The syntax is "preg_split('/specified symbol/',$str,-1,PREG_SPLIT_OFFSET_CAPTURE)".

The operating environment of this tutorial: windows7 system, PHP8 version, DELL G3 computer

php uses the specified symbol to split the string and convert it into an array, that is, Split the string on a specified symbol and pass the substrings into an array.

The first reaction when seeing this is to use the explode() function.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str = &#39;hypertext language programming&#39;;
var_dump($str);
$arr=explode(" ",$str);
var_dump($arr);
?>

As you can see, we use space symbols to split the string and pass the split substrings into the array as array elements.

So what else is there besides this? In fact, the preg_split() function provided by PHP can also use specified symbols to split strings and convert them into arrays

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str = &#39;hypertext language programming 1 2&#39;;
var_dump($str);
$arr=preg_split(&#39;/ /&#39;, $str, -1, PREG_SPLIT_OFFSET_CAPTURE);
var_dump($arr);
?>

As can be seen, in the above example we use space symbols to split the string and convert the string into an array.

Extended knowledge: explode() and preg_split() functions

1, explode() function

explode() function can be based on string splitting character splits a string, that is, it splits a string into several substrings based on the delimiter, and then combines these substrings into an array and returns it.

explode($delimiter, $string [, $limit])

The parameter description is as follows:

• $delimiter: The delimiter character used to split the string;
• $string: The string that needs to be split;
• $limit: Optional parameter, can be empty, specifies the number of array elements to be returned;
  •             If $limit is not empty and is a positive number, the returned array contains at most $limit elements, and the last element contains the remainder of $string;
  •             If $limit is not empty and is negative, all elements except the last $limit elements are returned;
  •             If $limit is 0, it will be treated as 1;
  •           If $limit is empty, all array elements are returned.

2. preg_split() function

preg_split() function splits a string through a regular expression.

preg_split ( string $pattern , string $subject [, int $limit = -1 [, int $flags = 0 ]] )

The parameter description is as follows:

• $pattern: The pattern used for matching, that is, the regular expression.
• $subject The string to be split.
• $limit: Optional parameter. If specified, the substrings obtained by limiting the separation will be limited to at most limit, and the last substring will contain all remaining parts. When the limit value is -1, 0 or NULL, it means "no limit". It is recommended to use NULL.
• $flags: optional parameter, which has 3 values.
  • If set to PREG_SPLIT_NO_EMPTY, preg_split() will return the separated non-empty part.
  • If set to PREG_SPLIT_DELIM_CAPTURE, bracket expressions in delimited patterns will be captured and returned.
  • If set to PREG_SPLIT_OFFSET_CAPTURE, the string offset will be appended to the return for each occurrence of a match.

            Note: This will change each element in the returned array so that each element becomes an array consisting of the 0th element being the separated substring and the 1st element being the offset of the substring in the subject. .

Return value: Returns an array composed of substrings obtained after using $pattern to split the subject string.

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