移动$ startOfLine指针

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 
<head> 
<title>Justifying Lines of Text</title> 
<link rel="stylesheet" type="text/css" href="common.css" /> 
<style> 
pre {font-family: Courier, monospace;} 
</style> 
</head> 
<body> 
<h1>Justifying Lines of Text</h1> 

<?php 

// The text to justify 

$myText = <<<END_TEXT 
But think not that this famous town has 
only harpooneers, cannibals, and 
bumpkins to show her visitors. Not at 
all. Still New Bedford is a queer place. 
Had it not been for us whalemen, that 
tract of land would this day perhaps 
have been in as howling condition as the 
coast of Labrador. 

END_TEXT; 

$myText = str_replace("\r\n", "\n", $myText); 

$lineLength = 40; // The desired line length 
$myTextJustified = ""; 
$numLines = substr_count($myText, "\n"); 
$startOfLine = 0; 

// Move through each line in turn 

for ($i=0; $i < $numLines; $i++) { 
    $originalLineLength = strpos($myText, "\n", $startOfLine) - $startOfLine; 
    $justifiedLine = substr($myText, $startOfLine, $originalLineLength); 
    $justifiedLineLength = $originalLineLength; 

    // Keep adding spaces between words until the desired 
    // line length is reached 

    while ($i < $numLines - 1 && $justifiedLineLength < $lineLength) { 
    for ($j=0; $j < $justifiedLineLength; $j++) { 
     if ($justifiedLineLength < $lineLength && $justifiedLine[$j] == " ") { 
     $justifiedLine = substr_replace($justifiedLine, " ", $j, 0); 
     $justifiedLineLength++; 
     $j++; 
     } 
    } 
    } 

    // Add the justified line to the string and move to the 
    // start of the next line 

    $myTextJustified .= "$justifiedLine\n"; 
    $startOfLine += $originalLineLength + 1;

上面一行的这本书的解释是“$ startOfLine指针移动到开始下一行的下一行的开始（加入到索引跳过。在换行符）

我的问题是：

不应该换行字符“\ n”包含两个字符为了跳过它，我们不应该加2变量$ startOfLine而不是1？

让我们来看看一个简单的例子：

$myText = "Hello\nworld\n" 

strpos ($myText, "\n", 0); //Returns 5, which is also the length of the first line "Hello" 
0+5+1; //Returns 6. It should be the index of the first character of the second line (w). But it's actually the index of the "n" right in front of it 
strpos ($myText, "\n", 6); //Returns 12 
12-6 //Returns 6. This should be the length of the second line. But the second line actually contains 5 characters.

但是，因为它应该，如果我更改为1〜2有什么问题的脚本将无法工作？

} 

?> 

<h2>Original text:</h2> 
<pre><?php echo $myText ?></pre> 

<h2>Justified text:</h2> 
<pre><?php echo $myTextJustified ?></pre> 

</body> 
</html>

来源

2013-03-03 Jermin Hu

请注意\ n和/ N正确的为\ n – 2013-03-03 19:45:36

感谢指点出来的区别。现在纠正了。 – 2013-03-03 19:50:13

我想我已经找出了这个问题。换行符“\ n”被PHP计算为单个字符。 – 2013-03-04 11:57:50

我认为你正在寻找wordwrap()的证明文本。

<?php 
$text = "The quick brown fox jumped over the lazy dog."; 
$newtext = wordwrap($text, 20, "<br />\n"); 

echo $newtext; 
?>

输出：

The quick brown fox<br /> 
jumped over the lazy<br /> 
dog.

来源

2013-03-03 19:54:40

我还没走那么远。在继续之前，我想完全理解这个脚本。 – 2013-03-03 20:43:00

移动$ startOfLine指针

回答

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