0. PHP&HTML混写
- 99乘法表的显示
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title></head><body><table><?phpfor ($i=1; $i <=9; $i++) { ?><tr><?phpfor ($j=1; $j <= $i ; $j++) {$ret = $i * $j;?><td style="border: 1px solid blue"><?php echo "$j * $i = $ret" ?></td><?php } ?><?php } ?></table></body></html>
— 数组展示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<?php
$stus = [
["name"=>"Tom", "age"=>24, "gender"=>"male", "address"=>"Beijing"],
["name"=>"Jack", "age"=>26, "gender"=>"male", "address"=>"Beijing"],
["name"=>"Rose", "age"=>42, "gender"=>"male", "address"=>"Beijing"],
["name"=>"Tony", "age"=>21, "gender"=>"male", "address"=>"Beijing"],
];
?>
<table>
<tr>
<th>姓名</th>
<th>年龄</th>
<th>性别</th>
<th>地址</th>
</tr>
<?php foreach($stus as $stu){ ?>
<tr>
<?php
foreach($stu as $val){ ?>
<td>
<?php echo $val; ?>
</td>
<?php } ?>
</tr>
<?php } ?>
</table>
</body>
</html>
1. 字符串操作
一个字符串 string 就是由一系列的字符组成，其中每个字符等同于一个字节。如果是汉字,根据编码计算所占字节数.
2. 定符串定义
- 单引号形式
``` // 不转义,所见即所得 $s1 = ‘hello’;
$s2 = ‘hello $s1 \n’;
- 双引号形式
```php
// 转义变量或转义特殊字符
$s1 = "hello";
$s2 = "hello $s1 \n";
3. 获取字符串长度函数
strlen() -返回给定的字符串
string的长度。strlen(string $string): int<?php header("content-type:text/html;charset=utf8"); $s1 = "helloworld"; echo strlen($s1); echo "<br>"; $s2 = "你好"; echo strlen($s2); echo "<br>"; ?>
4. 查找相关
strpos() — 查找字符串首次出现的位置
strpos(string $haystack, mixed $needle, int $offset = 0): int<?php header("content-type:text/html;charset=utf8"); // 可查找单个字符 $s1 = "helloworld"; echo strpos($s1,"o"); echo "<br>"; // 可查多个字符 $s2 = "哈喽你好你好"; echo strpos($s2, "你"); echo "<br>"; echo strpos($s2, "你好"); echo "<br>"; ?>strrpos() — 计算指定字符串在目标字符串中最后一次出现的位置, 反向查找;
strrpos(string $haystack, string $needle, int $offset = 0): int<?php header("content-type:text/html;charset=utf8"); // 可查找单个字符 $s1 = "helloworld"; echo strrpos($s1,"o"); echo "<br>"; // 可查多个字符 $s2 = "哈喽你好你好"; echo strrpos($s2, "你"); echo "<br>"; echo strrpos($s2, "你好"); echo "<br>"; ?>stripos() — 查找字符串首次出现的位置（不区分大小写）
stripos(string $haystack, string $needle, int $offset = 0): int<?php header("content-type:text/html;charset=utf8"); // 可查找单个字符 $s1 = "heLloworld"; echo stripos($s1,"l"); echo "<br>"; ?>strripos() — 计算指定字符串在目标字符串中最后一次出现的位置（不区分大小写）
strripos(string $haystack, string $needle, int $offset = 0): int<?php header("content-type:text/html;charset=utf8"); // 可查找单个字符 $s1 = "heLloworld"; echo strripos($s1,"l"); echo "<br>"; ?>
5. 统计相关
str_word_count — 返回字符串中单词的使用情况
format参数:
指定函数的返回值。当前支持的值如下：str_word_count(string $string, int $format = 0, ?string $characters = null): array|int- 0 - 返回单词数量(默认)
- 1 - 返回一个包含
string中全部单词的数组 - 2 - 返回关联数组。数组的键是单词在
string中出现的数值位置索引下标，数组的值是这个单词
注意:请注意，不支持多字节编码的字符串(不支持汉字统计)。
<?php
header("content-type:text/html;charset=utf8");
$str = "Hello fri3nd, you're
looking good today!";
echo str_word_count($str);
echo "<br>";
print_r(str_word_count($str, 0));
echo "<br>";
print_r(str_word_count($str, 1));
echo "<br>";
print_r(str_word_count($str, 2));
?>
substr_count — 计算字串出现的次数
substr_count( string $haystack, string $needle, int $offset = 0, ?int $length = null ): int```php <?php header(“content-type:text/html;charset=utf8”); $text = ‘This is a test’;
// 查找全部字符串内容 echo substr_count($text, ‘is’); // 2
// 字符串被简化为 ‘s is a test’，因此输出 1 echo substr_count($text, ‘is’, 3);
// 字符串被简化为 ‘s i’，所以输出 0 echo substr_count($text, ‘is’, 3, 3);
// 因为 5+10 > 14，所以生成警告 // echo substr_count($text, ‘is’, 5, 10);
// 输出 1，因为该函数不计算重叠字符串 $text2 = ‘gcdgcdgcd’; echo substr_count($text2, ‘gcdgcd’); ?>
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#### 6. 比较相关
- [strcmp](https://www.php.net/manual/zh/function.strcmp.php) — 二进制安全字符串比较<br />如果 `str1` 小于 `str2` 返回 < 0； 如果 `str1` 大于 `str2` 返回 > 0；如果两者相等，返回 0。(返回值为两串相减的差值)
```php
strcmp(string $str1, string $str2): int
<?php
header("content-type:text/html;charset=utf8");
echo strcmp("a", "b");
echo "<br>";
echo strcmp("a", "a");
echo "<br>";
echo strcmp("b", "a");
echo "<br>";
echo strcmp("abc", "z");
echo "<br>";
?>
strcasecmp — 二进制安全比较字符串（不区分大小写）
如果str1小于str2返回 < 0； 如果str1大于str2返回 > 0；如果两者相等，返回 0。strcasecmp(string $str1, string $str2): int<?php header("content-type:text/html;charset=utf8"); echo strcasecmp("a", "b"); echo "<br>"; echo strcasecmp("a", "a"); echo "<br>"; echo strcasecmp("b", "a"); echo "<br>"; echo strcasecmp("abc", "z"); echo "<br>"; echo strcasecmp("A", "a"); echo "<br>"; echo strcasecmp("ab", "Z"); echo "<br>"; ?>strncmp — 二进制安全比较字符串开头的若干个字符
该函数与 strcmp() 类似，不同之处在于你可以指定两个字符串比较时使用的长度（即最大比较长度）。
注意该比较区分大小写。strncmp(string $str1, string $str2, int $len): int<?php header("content-type:text/html;charset=utf8"); echo strncmp("abcc", "abcd", 3); echo "<br>"; ?>
7. 替换相关
str_replace — 子字符串替换
str_replace( mixed $search, mixed $replace, mixed $subject, int &$count = ? ): mixed```php <?php header(“content-type:text/html;charset=utf8”);
// 替换不会改变原字符串,会生成一个新字符串 $old = “aa”; $new = “AA”; $str = “aaBBaaBBaaBB”; $newStr = str_replace($old, $new, $str); echo $str; echo “
“; echo $newStr; echo “
“;// 查找值可以是字符串,也可以是数组 // 将字符串中所有出现的元音使用空串替换掉 // 赋值: Hll Wrld f PHP $vowels = array(“a”, “e”, “i”, “o”, “u”, “A”, “E”, “I”, “O”, “U”); $onlyconsonants = str_replace($vowels, “”, “Hello World of PHP”); echo $onlyconsonants; echo “
“;// 当查找值和替换值都使用数组,则值会一一对应替换, // 赋值: You should eat pizza, beer, and ice cream every day $phrase = “You should eat fruits, vegetables, and fiber every day.”; $healthy = array(“fruits”, “vegetables”, “fiber”); $yummy = array(“pizza”, “beer”, “ice cream”);
$newphrase = str_replace($healthy, $yummy, $phrase); echo $newphrase; echo “
“;// 赋值: 2 $str = str_replace(“ll”, “”, “good golly miss molly!”, $count); echo $count; echo “
“; echo $str;
?>
- [str_ireplace](https://www.php.net/manual/zh/function.str-ireplace.php) — str_replace 的忽略大小写版本
```php
str_ireplace(
mixed $search,
mixed $replace,
mixed $subject,
int &$count = ?
): mixed
<?php
header("content-type:text/html;charset=utf8");
// 替换不会改变原字符串,会生成一个新字符串
$old = "aa";
$new = "--";
$str = "aaBBAABBaaBBAABB";
$newStr = str_ireplace($old, $new, $str);
echo $str;
echo "<br>";
echo $newStr;
echo "<br>";
?>
str_repeat — 重复一个字符串
str_repeat(string $input, int $multiplier): string<?php header("content-type:text/html;charset=utf8"); echo str_repeat("Hello", 5); echo "<br>"; ?>substr_replace — 替换字符串的子串(根据指定的位置 进行替换)
substr_replace() 在字符串string的副本中将由start和可选的length参数限定的子字符串使用replacement进行替换。substr_replace( mixed $string, mixed $replacement, mixed $start, mixed $length = ? ): mixed```php $var = ‘ABCDEFGH:/MNRPQR/‘; echo “Original: $var
\n”;
/ 这两个例子使用 “bob” 替换整个 $var。/
echo substr_replace($var, ‘bob’, 0) . “
\n”;
echo substr_replace($var, ‘bob’, 0, strlen($var)) . “
\n”;
/ 将 “bob” 插入到 $var 的开头处。/
echo substr_replace($var, ‘bob’, 0, 0) . “
\n”;
/ 下面两个例子使用 “bob” 替换 $var 中的 “MNRPQR”。/
echo substr_replace($var, ‘bob’, 10, -1) . “
\n”;
echo substr_replace($var, ‘bob’, -7, -1) . “
\n”;
/ 从 $var 中删除 “MNRPQR”。/
echo substr_replace($var, ‘’, 10, -1) . “
\n”;
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#### 8. 转换相关
- [chr](https://www.php.net/manual/zh/function.chr.php) — 返回指定的字符
```php
chr(int $ascii): string
<?php
echo "48 - >" . chr(48) . "<br>";
echo "65 - >" . chr(65) . "<br>";
echo "97 - >" . chr(97) . "<br>";
?>
ord — 转换字符串第一个字节为 0-255 之间的值
ord(string $string): int<?php echo "0 - >" . ord("0") . "<br>"; echo "A - >" . ord("A") . "<br>"; echo "a - >" . ord("a") . "<br>"; echo "ab - >" . ord("ab") . "<br>"; // 只转换字符串的第一个字符 ?>ucfirst — 将字符串的首字母转换为大写
ucfirst(string $str): string```php <?php $foo = ‘hello world!’; $foo = ucfirst($foo); // Hello world!
$bar = ‘HELLO WORLD!’; $bar = ucfirst($bar); // HELLO WORLD! $bar = ucfirst(strtolower($bar)); // Hello world! ?>
- [ucwords](https://www.php.net/manual/zh/function.ucwords.php) — 将字符串中每个单词的首字母转换为大写
```php
ucwords(string $str, string $delimiters = " \t\r\n\f\v" ): string
<?php
$foo = 'hello world!';
$foo = ucwords($foo); // Hello World!
echo $foo . "<br>";
$foo = 'HELLO WORLD!';
$foo = ucwords($foo); // HELLO WORLD!
$foo = ucwords(strtolower($foo)); // Hello World!
echo $foo . "<br>";
$foo = 'hello|world!';
$foo = ucwords($foo); // Hello|world!
echo $foo . "<br>";
$foo = ucwords($foo, "|"); // Hello|World!
echo $foo . "<br>";
?>
- lcfirst — 使一个字符串的第一个字符小写
```php <?php $foo = ‘HelloWorld’; $foo = lcfirst($foo); // helloWorldlcfirst(string $str): string
$bar = ‘HELLO WORLD!’; $bar = lcfirst($bar); // hELLO WORLD! $bar = lcfirst(strtoupper($bar)); // hELLO WORLD! ?>
- [strtolower](https://www.php.net/manual/zh/function.strtolower.php) — 将字符串转化为小写
```php
strtolower(string $string): string
<?php
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = strtolower($str);
echo $str; // 打印 mary had a little lamb and she loved it so
?>
strtoupper — 将字符串转化为大写
strtoupper(string $string): string<?php $str = "Mary Had A Little Lamb and She LOVED It So"; $str = strtoupper($str); echo $str; // 打印 MARY HAD A LITTLE LAMB AND SHE LOVED IT SO ?>strip_tags — 从字符串中去除 HTML 和 PHP 标记
strip_tags(string $str, string $allowable_tags = ?): string<?php $text = '<p>Test paragraph.</p><!-- Comment --> <a href="#fragment">Other text</a>'; echo strip_tags($text); // 允许 <p> 和 <a> echo strip_tags($text, '<p><a>'); ?>str_shuffle — 随机打乱一个字符串
str_shuffle(string $str): string<?php $s = "Hello World"; echo $s . "<br>"; echo str_shuffle($s); ?>htmlspecialchars — 将特殊字符转换为 HTML 实体
htmlspecialchars( string $string, int $flags = ENT_COMPAT | ENT_HTML401, string $encoding = ini_get("default_charset"), bool $double_encode = true ): string| 字符 | 替换后 | | —- | —- | |
&
(& 符号) |&| |"
(双引号) |"
，除非设置了**ENT_NOQUOTES**| |'
(单引号) | 设置了**ENT_QUOTES**
后，'
(如果是**ENT_HTML401**
) ，或者'
(如果是**ENT_XML1**
、**ENT_XHTML**
或**ENT_HTML5**
)。 | |<
(小于) |<| |>
(大于) |>|
<?php
$s = "<a href='test'>Test</a>";
$new = htmlspecialchars($s, ENT_QUOTES);
echo $new; // <a href='test'>Test</a>
echo "<br>";
echo $s;
?>
9. 分割连接
substr — 返回字符串的子串
substr(string $string, int $offset, ?int $length = null): string<?php echo substr("abcdef", 3) . "<br>"; // 返回 "def" echo substr("abcdef", 0, -1) . "<br>"; // 返回 "abcde" echo substr("abcdef", 2, -1) . "<br>";; // 返回 "cde" echo substr("abcdef", 4, -4) . "<br>";; // 返回 ""; 在 PHP 8.0.0 之前，返回 false echo substr("abcdef", -3, -1) . "<br>";; // 返回 "de" ?>str_split — 将字符串转换为数组
str_split(string $string, int $split_length = 1): array<?php $str = "Hello Friend"; $arr1 = str_split($str); $arr2 = str_split($str, 3); print_r($arr1); print_r($arr2); ?>explode — 使用一个字符串分割另一个字符串
explode(string $separator, string $string, int $limit = PHP_INT_MAX): array<?php // 示例 1 $pizza = "piece1 piece2 piece3 piece4 piece5 piece6"; $pieces = explode(" ", $pizza); echo $pieces[0]; // piece1 echo '<br>'; echo $pieces[1]; // piece2 echo '<br>'; // 示例 2 $data = "foo:*:1023:1000::/home/foo:/bin/sh"; $arr = explode(":", $data); var_dump($arr); ?>implode — 将一个一维数组的值转化为字符串
implode(string $glue, array $pieces): string implode(array $pieces): string```php <?php $array = array(‘lastname’, ‘email’, ‘phone’);
echo implode($array); echo ‘
‘;echo implode(“,”, $array); echo ‘
‘;echo implode(“—“, $array); echo ‘
‘;// Empty string when using an empty array: var_dump(implode(‘hello’, array())); // string(0) “”
?>
- [join](https://www.php.net/manual/zh/function.join.php) — 别名 implode
- [strstr](https://www.php.net/manual/zh/function.strstr.php) — 查找字符串的首次出现, 返回 `haystack` 字符串从 `needle` 第一次出现的位置开始到 `haystack` 结尾的字符串。
```php
<?php
header("content-type:text/html;charset=utf8");
$s = "Hello php hello mysql";
echo strstr($s, "hello");
echo "<br>";
echo strstr($s, "php");
echo "<br>";
?>
stristr — strstr 函数的忽略大小写版本
<?php header("content-type:text/html;charset=utf8"); $s = "Hello php hello mysql"; echo stristr($s, "hello"); echo "<br>"; echo stristr($s, "php"); echo "<br>"; ?>strchr — 别名 strstr
10. 去除空白
ltrim — 删除字符串开头的空白字符（或其他字符）
<?php header("content-type:text/html;charset=utf8"); $s1 = " hello world "; echo "|" . $s1 . "|"; echo "<br>"; echo "|" . ltrim($s1) . "|"; echo "<br>"; ?>rtrim — 删除字符串末端的空白字符（或者其他字符）
<?php header("content-type:text/html;charset=utf8"); $s1 = " hello world "; echo "|" . $s1 . "|"; echo "<br>"; echo "|" . rtrim($s1) . "|"; echo "<br>"; ?>trim — 去除字符串首尾处的空白字符（或者其他字符）
<?php header("content-type:text/html;charset=utf8"); $s1 = " hello world "; echo "|" . $s1 . "|"; echo "<br>"; echo "|" . trim($s1) . "|"; echo "<br>"; ?>
11. 加密
- md5 — 计算字符串的 MD5 散列值
<?php header("content-type:text/html;charset=utf8"); $s1 = "heLloworld"; echo $s1; echo "<br>"; echo md5($s1); echo "<br>"; ?>
12. 反转字符串
- strrev — 反转字符串
<?php header("content-type:text/html;charset=utf8"); $s1 = "heLloworld"; echo $s1; echo "<br>"; echo strrev($s1); echo "<br>"; ?>
13. 序列化 serialize()
serialize() 返回字符串，此字符串包含了表示 value 的字节流，可以存储于任何地方。
这有利于存储或传递 PHP 的值，同时不丢失其类型和结构。
serialize(mixed $value): string
基本使用
<?php // 序列化数组 $animals = ["chicken", "duck", "goose",'dog','pig']; $aniStr = serialize($animals); echo $aniStr; echo "<br>"; // 序列化复杂数组 $animals = ["chicken", "duck", "goose",'dog','pig',100,true,[1,2,3]]; $aniStr = serialize($animals); echo $aniStr; echo "<hr>"; // 基本数据类型也可以进行序列化,但一般没必要 echo serialize(100) . "<br>"; //i:100; echo serialize(3.14) . "<br>"; //d:3.140000000000000124344978758017532527446746826171875; echo serialize(true) . "<br>"; //b:1; echo serialize(false) . "<br>"; //b:0; echo serialize("hello") . "<hr>"; //s:5:"hello"; ?>序列化原理
```php <?php function mySerialize($data){ $s = “;”;// 用来保存序列化字符串的变量$retS = “”;
// 获取类型$t = gettype($data);
// 根据不同的类型进行不同形式的拼接switch($t){
// 整数类型 case "integer": $retS .= "i:" . $data; break; // 小数类型 case "double": $retS .= "d:" . $data; break; // 布尔类型 case "boolean": $v = $data?"1":"0"; $retS .= "b:" . $v; break; // 字符串类型 case "string": $l = strlen($data); $retS .= "s:{$l}:" . "\"$data\""; break; // 数组类型 case "array": $retS .= "a:" . count($data) . ":{"; foreach ($data as $key => $value) { $retS .= mySerialize($key); $retS .= mySerialize($value); } $retS .= "}"; // 数组后面不拼接分号 $s = ""; break;} return $retS . $s; }
echo mySerialize(100) . “
“; //i:100;
echo mySerialize(3.14) . “
“; //d:3.140000000000000124344978758017532527446746826171875;
echo mySerialize(true) . “
“; //b:1;
echo mySerialize(false) . “
“; //b:0;
echo mySerialize(“hello”) . “
“; //s:5:”hello”;
// 序列化复杂数组
$animals = [“chicken”, “duck”, “goose”,’dog’,’pig’,100,3.14,true,[1,2,3]];
$aniStr = mySerialize($animals);
echo $aniStr;
echo “
“; ?>
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#### 14. 反序列化
**unserialize()** 对单一的已序列化的变量进行操作，将其转换回 PHP 的值。
```php
unserialize(string $str): mixed
序列化数据
i:100; d:3.14; b:1; b:0; s:5:"hello"; a:9:{i:0;s:7:"chicken";i:1;s:4:"duck";i:2;s:5:"goose";i:3;s:3:"dog";i:4;s:3:"pig";i:5;i:100;i:6;b:1;i:7;a:3:{i:0;i:1;i:1;i:2;i:2;i:3;}i:8;s:3:"php";}反序列化
<?php $file = fopen("test.txt","r"); do{ $content = fgets($file); $data = unserialize($content); var_dump($data); }while($content); fclose($file); echo "<hr>";
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