PHP splitting and synthesizing string function analysis

Split the string

The splitting of the string is achieved through the explode()function. The explode() function splits a string according to the specified rules, and the return value is an array.

The syntax format is as follows:

explode(separator,string,limit)

The parameter list of the function is as follows:

Parameters	Description
separator	Required parameters, specify the split identifier.
string	Required parameters, specify the string to be split
limit	can Select parameters to specify the number of array elements returned

#Note: If separator is an empty string (" "), explode() will return false; if separator contains The value cannot be found in string, then the explode() function will return an array containing a single element of string.

If the limit parameter is set, the returned array contains up to limit elements, and the last element will contain the remainder of the string; if the limit parameter is a negative number, all but the last -limit elements are returned element.

Use the explode() function to split the string. The code to implement it is as follows:

<?php
 $str = "PHP手册@HTML手册@CSS手册@JAVA手册";
 $array = explode("@",$str);                  //使用@分割字符串
 var_dump($array);                            //输出字符串分割后的结果
?>

As can be seen from the above code, when splitting the string $str, use "@" Split as a split identifier, split into 4 array elements, and finally use the var_dump() function to output the elements in the array.

The running results are as follows:

array(4) {

                                                                                             Manual"

##                                                                                                                                                                                                                                                                            [1]=> string(10) "HTML Manual" "CSS Manual"

              [3]=> string(10) "JAVA Manual"

}

Note: By default, the

index of the first element of the array is 0. For related knowledge about arrays, please refer to PHP Chinese website Array array

.

In addition to using the var_dump() function, you can also use the echo statement to output array elements. The difference between the two is that the var_dump() function outputs an array column, while using echo The statement outputs a single element in the array. Replace "var_dump($array);

" with the following code to output the elements in the array.

<?php
$str = "PHP手册@HTML手册@CSS手册@JAVA手册";
$array = explode("@",$str);                  //使用@分割字符串
echo $array[0];                              //输出数组中的第1个元素
echo $array[1];                              //输出数组中的第2个元素
echo $array[2];                              //输出数组中的第3个元素
echo $array[3];                              //输出数组中的第4个元素
?>

The output result is: PHP Manual HTML Manual CSS Manual JAVA Manual

Explanation: How to run the above two methods of outputting split strings The results will appear slightly different.

Synthetic string

The implode() function can combine the contents of an array into a new string. The syntax format is as follows:

implode(separator,array)

The parameter separator is optional. Specifies what is placed between array elements. Default is "" (empty string). The parameter array is required and must be combined into an array of strings.

Apply the implode() function to concatenate the contents of the array with * as the delimiter to form a new string. The example code is as follows:

<?php
$str = "PHP手册@HTML手册@CSS手册@JAVA手册";
$array = explode("@",$str);                  //使用@分割字符串
$arr = implode("*",$array);                  //将数组使用*组合成字符串
echo $arr;                                   //输出字符串
?>

Output results For:

PHP Manual*HTML Manual*CSS Manual*JAVA Manual

Explanation:

implode() function and explode() function are two There are two relative functions, one used to synthesize strings and one used to separate strings.

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