Complete list of PHP array and string conversion functions_PHP tutorial

1. Convert a string into an array
str_split() is used to convert a string into an array
Syntax:

$str="www.jbxue.com";
print_r(str_split($str));
?>

2. String splitting function
explode() function splits the string into arrays.
Syntax:
explode(separator,string,limit)
//separator is required and specifies the basis for splitting the string, for example: " " (space) "|" "," etc.
//string is required, it is the string to be operated on
//limit is optional and specifies the maximum number of array elements returned.
Example:

$types="doc|docx|ppt|pptx|xls|xlsx|zip|rar";
print_r(explode("|",$types));
?>

3. Convert an array into a string
Use the implode() function to combine the array elements into a string
Syntax:
implode(separator,array)//seperator is optional and specifies the content placed between array elements. The default is "" (empty string)
implode(separator,array)//seperator是可选的，规定数组元素之间放置的内容，默认是“”（空字符串）

//array is required and is an array to be combined into a string

tips: Althoughseparator parameters is optional. However, for backward compatibility, it is recommended that you use two parameters. implode() can accept two parameter orders. However, due to historical reasons, explode() does not work. You must ensure that the
separator parameter comes before the string parameter. Example:

<?php<br />$arr = array('Hello','World!','Beautiful','Day!');<br />echo implode(" ",$arr);<br />?>

4. Find another character in a string
Use strpos() or strstr() function
The strpos() function returns the position of the first occurrence of a string in another string.
If the string is not found, return false.
Syntax:

//string is required, indicating the searched string
//find is required, indicating the searched string
//start is optional. Specifies the location from which to start the search.

tip:
This function is case sensitive
Example:

$str="HellO neo";
$find1="O";
$find2="o";
echo strpos($str,$find1);
echo "< ;br/>";
echo strpos($str,$find2);
?>

Output result:
Copy the code. The code is as follows:

4
8

5. Intercept some characters in the string
substr() function returns a part of the string
Syntax:

//string is required and specifies that a part of the string should be returned.
/*Required. Specifies where in the string to begin.
Positive number - starts at the specified position in the string
Negative number - starts at the specified position from the end of the string
0 - starts at the first character in the string
*/
/*Optional. Specifies the length of the string to be returned. The default is until the end of the string.
Positive number - Returns
from the position of the start parameter Negative number - Returns
*/

from the end of the string

tips:
If start is a negative number and length is less than or equal to start, then length is 0.
Example;

$str="Hello world!";
echo substr($str,0);
echo "
";
echo substr($str,6,5) ;
?>

6. Get the length of the string
The strlen() function is used to calculate the length of the string.
Example:

$str="Hello world!";
echo strlen($str);
?>
//The output result is 12

7. Convert the string to uppercase
The strtoupper() function converts the string to uppercase.
Example:

$str="Hello world!";
echo strtoupper($str);
?>
//The output result is: HELLO WORLD!

8. Convert the string to lowercase
The strtolower() function converts the string to lowercase.
Example:

$str="Hello World!";
echo strtolower($str);
?>

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