php 字符串替换函数

<?php
$arr = array("blue","red","green","yellow");
print_r(str_ireplace("red","pink",$arr,$i));
echo "Replacements: $i";
?>

输出：

Array
(
[0] => blue
[1] => pink
[2] => green
[3] => yellow
)

<?php
$find = array("Hello","world");
$replace = array("B");
$arr = array("Hello","world","!");
print_r(str_ireplace($find,$replace,$arr));
?>输出：

Array
(
[0] => B
[1] =>
[2] => !
)

<?php
substr_replace('eggs','x',-1,-1); //eggxs
substr_replace('eggs','x',-1,-2); //eggxs
substr_replace('eggs','x',-1,-2); //eggxs
?> Same as:
<?php
substr_replace('eggs','x',-1,0); //eggxs
?>

<?php
substr_replace('huevos','x',-2,-2); //huevxos
substr_replace('huevos','x',-2,-3); //huevxos
substr_replace('huevos','x',-2,-3); //huevxos
?> Same as:

<?php
substr_replace('huevos','x',-2,0); //huevxos
?>

function unescape($str) {
$str = rawurldecode($str);
preg_match_all("/%u.{4}|&#x.{4};|&#d+;|.+/U",$str,$r);
$ar = $r[0];
foreach($ar as $k=>$v) {
if(substr($v,0,2) == "%u")
$ar[$k] = iconv("UCS-2","GBK",pack("H4",substr($v,-4)));
elseif(substr($v,0,3) == "&#x")
$ar[$k] = iconv("UCS-2","GBK",pack("H4",substr($v,3,-1)));
elseif(substr($v,0,2) == "&#") {
$ar[$k] = iconv("UCS-2","GBK",pack("n",substr($v,2,-1)));
}
}
return join("",$ar);
}

function unescape($str){
$ret = '';
$len = strlen($str);
for ($i = 0; $i < $len; $i++){
if ($str[$i] == '%' && $str[$i+1] == 'u'){
$val = hexdec(substr($str, $i+2, 4));
if ($val < 0x7f) $ret .= chr($val);
else if($val < 0x800) $ret .= chr(0xc0|($val>>6)).chr(0x80|($val&0x3f));
else $ret .= chr(0xe0|($val>>12)).chr(0x80|(($val>>6)&0x3f)).chr(0x80|($val&0x3f));
$i += 5;
}
else if ($str[$i] == '%'){
$ret .= urldecode(substr($str, $i, 3));
$i += 2;
}
else $ret .= $str[$i];
}
return $ret;
}

function smssubstr($string, $length) {
 if(strlen($string) <= $length) {
  return $string; 
 }
 $strcut = '';
 for($i = 0; $i < $length; $i++) {
  $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
 }
 return $strcut;
}

for($i=1; $i<=$smsnum; $i++){
 ${'smscontent'.$i} = smssubstr($message,$smsper);
 $message = str_replace(${'smscontent'.$i},"",$message);
}