字符串的一些php操作

echo "<br/>----------------explode--------------<br/>";
$str = "tea,milk,coffee,juice";
$arr = explode(',',$str);
echo "<pre>";
print_r($arr);

$arr = explode(',',$str,2);//分割为2个数组,多余的都放最后;
print_r($arr);

echo "<br/>------------implode数组组合为字符串;------------------<br/>";
$drink_arr = array(
"tea",
"milk",
"coffee",
"juice"
);

$drink_str = implode('|',$drink_arr);

echo "drink_str = ".$drink_str;

echo "<br/>-------------比较字符串大小int strcmp-----------------<br/>";
$a='a';
$b='b';
$result=strcmp($a,$b);//$a<$b返回负数,$a>$b返回正数，=返回0;
echo $result;
echo "<br/>-----------parse_str返回数组-------------------<br/>";
$arr = array();
parse_str("id=23&name=John%20Adams",$arr);
echo $arr['id']."<br />";
echo $arr['name'];

echo "<br/>------------------------------<br/>";
$str = 'How are you?';
echo '原字符串：';
echo '<br/>';

echo $str;
echo '<br/>';
echo '<br/>';

$arr1 = str_split($str);//一个字母一个元素
$arr2 = str_split($str, 3);//3个字母一个元素：

echo '<pre>';
print_r($arr1);
print_r($arr2);
echo '</pre>';

echo "<br/>------------------------------<br/>";
$str1 = 'This is a secret';
$str2 = 'root';

echo '原字符串：';
echo '<br/>';
echo 'str1='.$str1;
echo '<br/>';
echo 'str2='.$str2;
echo '<br/>';
echo '<br/>';

echo '使用md5加密：';
echo '<br/>';
echo "md5($str1)=".md5($str1);
echo '<br/>';
echo "md5($str2)=".md5($str2);

echo '<br/>';
echo '<br/>';

echo '使用sha1加密：';
echo '<br/>';
echo "sha1($str1)=".sha1($str1);
echo '<br/>';
echo "sha1($str2)=".sha1($str2);

echo "<br/>-------------ucfirst字符串第一个字母大写 ucwords每个单词第一个字母转化为大写-----------------<br/>";
echo ucfirst($str1);
echo '<br/>';

echo ucWords($str1);
echo "<br/>------------------chr  ord------------<br/>";
echo chr(98);//把ASCII转化为字符串;
echo ord('b');//把字符串转化为ASCII
echo "<br/>------------------------------<br/>";
echo "Operation System:".  PHP_OS;
echo "<br>";
echo "Php version:" .  PHP_VERSION . "\n";

echo "<br/>------------------------------<br/>";
echo $_SERVER['HTTP_ACCEPT_LANGUAGE'];
echo "<br>";

echo $_SERVER['REMOTE_ADDR'];