PHP开发笔记系列（二）-字符串使用
经过了《PHP开发笔记系列（一）-PDO使用》，今天开了关于PHP开发中字符串的处理，《PHP开发笔记系列（二）-字符串使用》，形成《PHP开发笔记系列》的第二篇。
字符串是任何开发语言都必须处理的，在PHP中字符串可以使用单引号（'）或双引号（"）进行定义。那单引号和双引号不同之处在哪？那就是双引号中的变量会被变量值替换，而单引号中的内容将原样输出。下面将日常程序开发中会碰到的字符串处理场景整理。
1. 以数组形式访问字符串（strlen）
file:str-lengh.php
url:http://localhost:88/str/str-lengh.php
<?php $word = 'Hello, Ryan!';
echo "String($word)'s length: ".strlen($word)."<br/>";
// for循环访问数组
//for($i=0; $i<strlen echo></strlen>";
//}
// while循环访问数组
$i=0;
while($i<strlen echo></strlen>";
$i++
}
?>
file:str-strip-tags.php
url:http://localhost:88/str/str-strip-tags.php
<?php // 字符串中的所有html标签都闭合
$text = "<h1>hello world!<h1>hello world!</h1><h1>hello world!</h1>";
// 输出原始的字符串内容
echo "Original Text:";
echo $text."<br>";
// 去除所有html标签后进行输出
echo "Destination Text(After strip_tags)"."<br>";
echo strip_tags($text)."<br>";
// 字符串中的html标签不闭合
$text = "<h1>hello world!";
// 去除所有html标签后进行输出
echo "Original Text:";
echo $text."<br>";
// 去除所有html标签后进行输出
echo "Destination Text(After strip_tags)"."<br>";
echo strip_tags($text)."<br>";
?>
</h1>
file:str-entities.php
url:http://localhost:88/str/str-entities.php
<?php $text = "hello & world!";
echo $text."<br/>";
echo rawurlencode($text)."<br>";
?>
file:str-wordwrap.php
url:http://localhost:88/str/str-wordwrap.php
<?php $text = "This document covers the JavaTM 2 Platform Standard Edition 5.0 Development Kit (JDK 5.0). Its external version number is 5.0 and internal version number is 1.5.0. For information on a feature of the JDK, click on its component in the diagram below.";
echo "Original text:"."<br/>";
echo $text."<br>";
echo $text."<hr>";
echo "Destination text(after wrap):"."<br>";
echo wordwrap($text, 50, "<br>")."<br>";
?>
file:str-strpos.php
url:http://localhost:88/str/str-strpos.php
<?php $text = "hello world!";
echo strpos($text, "e");
?>
file:str-strreplace.php
url:http://localhost:88/str/str-strreplace.php
<?php $text = "This document covers the JavaTM 2 Platform Standard Edition 5.0 Development Kit (JDK 5.0). Its external version number is 5.0 and internal version number is 1.5.0. For information on a feature of the JDK, click on its component in the diagram below.";
echo "Original text:"."<br/>";
echo $text."<br>";
echo "<hr>";
echo "Destination text(replace):"."<br>";
echo str_replace(" ", "__", $text)."<br>";
?>
file:str-compare.php
url:http://localhost:88/file/str-compare.php
<?php $main_str = 'hello world';
$str = 'hello world, Ryan!';
echo substr_compare($main_str, $str, 0);
?>
file:str-sub.php
url:http://localhost:88/file/str-sub.php
<?php $str = 'hello world,today is sunday!';
$start = strpos($str, ',');
$newStr = substr($str, $start+1);
echo 'Original String: '.$str.'<br/>';
echo 'Destination String: '.$newStr.'<br>';
?>
file:str-count.php
url:http://localhost:88/file/str-count.php
<?php $str = 'abcdefgacef';
echo substr_count($str, 'a');
?>
file:str-explode-implode.php
url:http://localhost:88/str/str-explode-implode.php
<?php $text = "This document covers the JavaTM 2 Platform Standard Edition 5.0 Development Kit (JDK 5.0). Its external version number is 5.0 and internal version number is 1.5.0. For information on a feature of the JDK, click on its component in the diagram below.";
echo "Original text:"."<br/>";
echo $text."<br>";
echo "<hr>";
$sentenses = explode(". ", $text);
echo "Destination text(explode):"."<br>";
foreach ($sentenses as $sentense){
echo $sentense."<br>";
}
echo "<hr>";
$newText= implode($sentenses, ". ");
echo "Destination text(implode):"."<br>";
echo $newText."<br>";
?>
file:str-trim.php
url:http://localhost:88/str/str-trim.php
<?php $text = " hello world! ";
echo "Original text:"."<br/>";
echo strlen($text)."<br>";
echo "<hr>";
echo "Destination text(trim):"."<br>";
echo strlen(trim($text))."<br>";
?>
file:str-printf.php
url:http://localhost:88/str/str-printf.php
<?php $format = 'hello, %2$s, userNo: %1$s';
$who = 'Ryan';
$no = '10';
echo printf($format, $no, $who);
?>
