


The following is a detailed explanation: ///\
string urlencode ( string str)
Returns a string. All non-alphanumeric characters in this string except -_. will be replaced with percent signs ( %) followed by two hexadecimal digits, and spaces are encoded as plus signs (+). This encoding is the same as the encoding of WWW form POST data, and the same encoding as the application/x-www-form-urlencoded media type. For historical reasons, this encoding differs from the RFC1738 encoding (see rawurlencode()) in encoding spaces as plus signs (+). This function facilitates encoding a string and using it in the request part of the URL, and it also facilitates passing variables to the next page: Example 1. urlencode() Example
echo '' ;
?>
Note: Be careful with variables that match HTML entities. Characters like &, © and £ will be parsed by the browser and the actual entity will be used instead of the expected variable name. This is obvious confusion, and the W3C has been warning people about it for several years. Reference address: http://www.w3.org/TR/html4/appendix/notes.html#h-B.2.2 PHP supports changing the parameter separator to the semicolon recommended by W3C through the arg_separator .ini directive. Unfortunately most user agents do not send form data in semicolon delimited format. A simpler solution is to use & instead of & as the delimiter. You don't need to modify PHP's arg_separator for this. Leave it still & and just use htmlentities(urlencode($data)) to encode your URL.
Example 2. urlencode() and htmlentities() Example
echo '';
?>
string urlencode (string str)
Returns a string in which all non-alphanumeric characters except -_. will be replaced with a percent sign (%) followed by two hexadecimal digits. This encoding, described in RFC 1738, is intended to protect literal characters from being interpreted as special URL delimiters, and to protect the URL format from being garbled by character conversions used by the transport medium (like some mail systems). For example, if you want to include the password in the FTP URL:
Example 1. rawurlencode() Example 1
echo '';
?>
Or, if you want to pass information through the PATH_INFO component of the URL:
Example 2. rawurlencode( ) Example 2
echo '';
?>
When decoding, you can use the corresponding urldecode() and rawurldecode(). Correspondingly, rawurldecode() will not decode the plus sign ('+') into a space, but urldecode() can. Here's a detailed example:
string urldecode ( string str)
Decode any %## in the given encoded string. Returns the decoded string. Example 1. urldecode() example
$a = explode ('&', $QUERY_STRING);
$i = 0;
while ($i $b = split('=', $a[$i ]);
echo 'Value for parameter ', htmlspecialchars(urldecode($b[0])),
' is ', htmlspecialchars(urldecode($b[1])), "
$i++;
}
?>
string rawurldecode ( string str)
Returns a string, the percent sign ( %) followed by two hexadecimal digits will be replaced with literal characters.
Example 1. rawurldecode() Example
echo rawurldecode('foo%20bar%40baz'); // foo bar@baz
?>
However, one thing to note is that the string decoded by urldecode() and rawurldecode() is encoded in UTF-8 format. If the URL contains Chinese and the page setting is not UTF-8, The decoded string must be converted before it can be displayed normally!
There is another problem, that is, the obtained URL is not in the format of %%nn n={0..F}, but in the format of %unnnn n={0..F}. In this case, use urldecode() and rawurldecode() cannot be decoded correctly, and the following function must be used to decode correctly:
function utf8RawUrlDecode ($source)
{
$decodedStr = "";
$pos = 0;
$len = strlen ($source);
while ($pos $charAt = substr ($source, $pos, 1);
if ($charAt == '%') {
$pos++;
$charAt = substr ($ source, $pos, 1);
if ($charAt == 'u') {
// we got a unicode character
$pos++;
$unicodeHexVal = substr ($source, $ pos, 4);
$unicode = hexdec ($unicodeHexVal);
$entity = "". $unicode . ';';
$decodedStr .= utf8_encode ($entity);
$pos += 4;
}
else {
// we have an escaped ascii character
$hexVal = substr ($source, $pos, 2);
$decodedStr . = chr (hexdec ($hexVal));
$pos += 2;
}
} else {
$decodedStr .= $charAt;
$pos++;
}
}
return $decodedStr;
}

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

查找方法:1、用strpos(),语法“strpos("字符串值","查找子串")+1”;2、用stripos(),语法“strpos("字符串值","查找子串")+1”。因为字符串是从0开始计数的,因此两个函数获取的位置需要进行加1处理。


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