str_split

(PHP 5, PHP 7, PHP 8)

str_split将字符串转换为数组

说明

str_split(string $string, int $length = 1): array

将一个字符串转换为数组。

参数

string

输入字符串。

length

每一段的长度。

返回值

如果指定了可选的 length 参数,返回数组中的每个元素长度均为 length 的块,除了最后一个块,如果字符串不是均匀划分,则可能会更短。默认 length1,这意味着每个块的大小是一个字节。

错误/异常

如果 length 小于 1,将会抛出 ValueError

更新日志

版本 说明
8.0.0 如果 length 小于 1,现在会抛出 ValueError;之前会触发 E_WARNING 级别的错误且函数会返回 false

范例

示例 #1 str_split() 使用范例

<?php

$str
= "Hello Friend";

$arr1 = str_split($str);
$arr2 = str_split($str, 3);

print_r($arr1);
print_r($arr2);

?>

以上例程会输出:

Array
(
    [0] => H
    [1] => e
    [2] => l
    [3] => l
    [4] => o
    [5] =>
    [6] => F
    [7] => r
    [8] => i
    [9] => e
    [10] => n
    [11] => d
)

Array
(
    [0] => Hel
    [1] => lo
    [2] => Fri
    [3] => end
)

注释

注意:

在处理多字节字符时,str_split() 会按字节数转换,而非字符数。使用 mb_str_split() 将字符串拆分为码点。

参见

add a note

User Contributed Notes 3 notes

up
0
Julian
1 month ago
The function str_split() is not 'aware' of words. Here is an adaptation of str_split() that is 'word-aware'.

<?php

$array
str_split_word_aware(
   
'In the beginning God created the heaven and the earth. And the earth was without form, and void; and darkness was upon the face of the deep.',
   
32
);

var_dump($array);

/**
  * This function is similar to str_split() but this function keeps words intact; it never splits through a word.
  *
  * @return array<int, string>
  */
function str_split_word_aware(string $string, int $maxLengthOfLine): array
{
    if (
$maxLengthOfLine <= 0) {
        throw new
RuntimeException(sprintf('The function %s() must have a max length of line at least greater than one', __FUNCTION__));
    }
   
   
$lines = [];
   
$words = explode(' ', $string);

   
$currentLine = '';
   
$lineAccumulator = '';
    foreach (
$words as $currentWord) {

       
$currentWordWithSpace = sprintf('%s ', $currentWord);
       
$lineAccumulator .= $currentWordWithSpace;
        if (
strlen($lineAccumulator) < $maxLengthOfLine) {
           
$currentLine = $lineAccumulator;
            continue;
        }

       
$lines[] = $currentLine;

       
// Overwrite the current line and accumulator with the current word
       
$currentLine = $currentWordWithSpace;
       
$lineAccumulator = $currentWordWithSpace;
    }

    if (
$currentLine !== '') {
       
$lines[] = $currentLine;
    }

    return
$lines;
}

?>

OUTPUT:

<?php

array(5) {
  [
0]=> string(29) "In the beginning God created "
 
[1]=> string(30) "the heaven and the earth. And "
 
[2]=> string(28) "the earth was without form, "
 
[3]=> string(27) "and void; and darkness was "
 
[4]=> string(27) "upon the face of the deep. "
}

?>
up
-4
alex-glebe at mail dot ru
2 months ago
Empty string Does'n returns Empty array!

$arr0 = str_split("");
print_r($arr0);

Array
(
    [0] =>
)
up
-7
lskatz at gmail dot com
14 years ago
A good use of str_split is reverse translating an amino acid sequence.

<?php
/* reverse translate an aa sequence using its dna counterpart */
function reverseTranslate($aaSeq,$ntSeq){
 
$nt=str_split($ntSeq,3);
 
$aa=str_split($aaSeq,1);
 
$gapChar=array('*','-');

 
$numAa=count($aa);
 
$ntIndex=0;
 
$newNtSeq="";
  for(
$i=0;$i<$numAa;$i++){
   
// if the aa is a gap, then just put on a gap character
   
if(in_array($aa[$i],$gapChar)){
     
$newNtSeq.='---';
    }
    else{
     
$newNtSeq.=$nt[$ntIndex];
     
$ntIndex++;
    }
  }
  return
$newNtSeq;
}
?>
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