写给程序员的 PHP 语法快速入门

<?php include 'header.php';?>
<?php
 /*
 本文目的:总览 PHP 的主要语法，并供日后备忘。
 阅读指南：本文不是文档。通过通读本文，可以了解 PHP 基本的语法及一些常用的方法。读者可以将其与其他语言比较，理解其意图与含义。
 目标读者：具有程序设计基础知识，理解面向对象程序设计基本概念的程序员。
 */

 // 导入
 include('header.php');
 require('core.php');

 // echo 内容支持 HTML
 echo "<strong>This is a bold text.</strong>";

 // 变量
 $NAME = 'BREEZE';
 $name = 'breeze'; // 变量名对大小写敏感
 // 1ABC = 25; 变量名不能以数字起始
 $variable = 'name';
 echo $name;
 echo $name.$NAME; // breezeBREEZE
 echo $$variable; // breeze

 // 常量
 define("CASE_SENSITIVE_CONSTANT","CONSTANT_SAMPLE",true); // 定义一个具有大小写敏感的名称的常量
 define("CASE_INSENSITIVE_CONSTANT","CONSTANT_SAMPLE",false); // 定义一个具有大小写不敏感的名称的常量
 define("CONSTANT","CONSTANT_SAMPLE"); // 默认情况下，常量名称的大小写不敏感。然而，名称大小写敏感的常量依然以小写形式储存，因此在定义一个大小写敏感常量之后再定义一个同名小写常量将发生错误
 echo CASE_SENSITIVE_CONSTANT;

 $string1 = '9';
 $int1 = -42;
 $float1 = 42.09;
 $boolean1 = true; // 另一个布尔值为 false
 echo($string1+int1); // -33

 // 方法
 function getName() { // 方法名对大小写不敏感，且只能以字母或下划线（_）起始
  $name = 'Breeze';
  echo $name; // 将 echo 'Breeze' 而非之前定义的 'breeze' 
  return $name;
 }

 function getGlobalName() {
  global $name;
  echo $name; // 将 echo 之前定义的 'breeze' 
 } // 返回 NULL

 function echoName($name='Alice') {
  echo $name;
 }

 echoName('Alice'); // Alice
 echoName(); // Alice

 // 算术
 $num1 =4;
 $num2 =3;
 echo $num1/$num2; // 1.33333333333
 echo $num1%$num2; // 1
 $num1++;
 --$num2; 
 $num2 += $num1; // $num2 = 7
 $t = true;
 $f = false;

 // 逻辑运算
 $booleanResult = $t and $f or $t xor $f && $t || !$f
 
 if ($num1 > 1 and $num1 < 1 or $num1 >= 0 xor $num2 <= 5 && $num1 != $num2 || !($num1 <> $num2)) {
 } else if ($num1 == $num2) { // 相等
  echo $num1++;
 } else if ($num1 === $num2) { // 相等且类型相同 (全等)
  echo $num1--;
 } else if ($num1 !== $num2) { // 不等或类型不同 (不全等)
  echo $num2++;
 } else {
  echo $num2--;
 }

 // 数组
 $peopleNumeric = array("Alice","Bob");
 $peopleAssociative = array("Alice"=>"17","Bob"=>"18");
 $peopleMultiDimensional = array("Alice"=>array('C','Z'),"Bob"=>array('H','W','L'));
 echo $peopleNumber[0]; // Alice
 echo $peopleAssociative['Alice']; // 17
 echo $peopleMultiDimensional['Bob'][2]; // L

 // 循环
 $intForWhile = 1;
 while ($intForWhile<9) {
  echo "Current: ".$intForWhile;
  $intForWhile++;
 }

 do {
  echo "Current: ".$intForWhile;
  $intForWhile++;
 } while($intForWhile<20) 


 for ($i = 0;$i <9;$i++) {
  echo "Current: ".$i;
  if ($i==7) {
   continue;
  }   
 }

 foreach($peopleNumeric as $ $person) {
  echo $person; // Alice Bob
 }

 // switch
 switch ($peopleNumber[0]) {
  case "Alice":
   echo "Alice";
   break;
  case "bob":
  case "Bob":
   echo "Bob";
   break;
  default:
   echo "No match";
 }


 // superglobals
 echo $_SERVER['SCRIPT_NAME']; // including $GLOBALS, $_REQUEST, $_POST, $_GET, $_FILES, $_ENV, $_COOKIE, $_SESSION
 echo $_SERVER['SCRIPT_FILENAME'];
 echo $_SERVER['SCRIPT_URL'];
 echo $_SERVER['HTTP_HOST'];
 echo $_SERVER['PHP_SELF'];
 echo $_SERVER['SERVER_ADDR'];
 echo $_SERVER['SERVER_NAME'];
 echo $_SERVER['SERVER_PORT'];
 echo $_SERVER['REMOTE_ADDR'];
 echo $_SERVER['REMOTE_HOST'];
 echo $_SERVER['REMOTE_PORT'];

 // 文件操作
 $file=fopen("file.txt", "w"); // mode: r, w, a, x, r+, w+, a+, x+. a mode won't erase data
 fwrite($file,"TEXT\n"); // the original content is erased
 fclose($file); // return true or false
 $file=fopen("file.txt", "a");
 fwrite($file,"TEXT\n"); // content of the file: TEST\nTEST\n
 fclose($file);
 $content=file("file.txt"); 
 $count=count($content); // get length of the array
 foreach ($content as $line) {
  echo $line."\n";
 }

?>

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<?php include 'header.php';?>

<?php

本文目的:总览 PHP 的主要语法，并供日后备忘。

阅读指南：本文不是文档。通过通读本文，可以了解 PHP 基本的语法及一些常用的方法。读者可以将其与其他语言比较，理解其意图与含义。

目标读者：具有程序设计基础知识，理解面向对象程序设计基本概念的程序员。

// 导入

include('header.php');

require('core.php');

// echo 内容支持 HTML

echo "<strong>This is a bold text.</strong>";

// 变量

$NAME = 'BREEZE';

$name = 'breeze'; // 变量名对大小写敏感

// 1ABC = 25; 变量名不能以数字起始

$variable = 'name';

echo $name;

echo $name.$NAME; // breezeBREEZE

echo $$variable; // breeze

// 常量

define("CASE_SENSITIVE_CONSTANT","CONSTANT_SAMPLE",true); // 定义一个具有大小写敏感的名称的常量

define("CASE_INSENSITIVE_CONSTANT","CONSTANT_SAMPLE",false); // 定义一个具有大小写不敏感的名称的常量

define("CONSTANT","CONSTANT_SAMPLE"); // 默认情况下，常量名称的大小写不敏感。然而，名称大小写敏感的常量依然以小写形式储存，因此在定义一个大小写敏感常量之后再定义一个同名小写常量将发生错误

echo CASE_SENSITIVE_CONSTANT;

$string1 = '9';

$int1 = -42;

$float1 = 42.09;

$boolean1 = true; // 另一个布尔值为 false

echo($string1+int1); // -33

// 方法

function getName() { // 方法名对大小写不敏感，且只能以字母或下划线（_）起始

$name = 'Breeze';

echo $name; // 将 echo 'Breeze' 而非之前定义的 'breeze'

return $name;

}

function getGlobalName() {

global $name;

echo $name; // 将 echo 之前定义的 'breeze'

} // 返回 NULL

function echoName($name='Alice') {

echo $name;

}

echoName('Alice'); // Alice

echoName(); // Alice

// 算术

$num1 =4;

$num2 =3;

echo $num1/$num2; // 1.33333333333

echo $num1%$num2; // 1

$num1++;

--$num2;

$num2 += $num1; // $num2 = 7

$t = true;

$f = false;

// 逻辑运算

$booleanResult = $t and $f or $t xor $f && $t || !$f

if ($num1 > 1 and $num1 < 1 or $num1 >= 0 xor $num2 <= 5 && $num1 != $num2 || !($num1 <> $num2)) {

} else if ($num1 == $num2) { // 相等

echo $num1++;

} else if ($num1 === $num2) { // 相等且类型相同 (全等)

echo $num1--;

} else if ($num1 !== $num2) { // 不等或类型不同 (不全等)

echo $num2++;

} else {

echo $num2--;

}

// 数组

$peopleNumeric = array("Alice","Bob");

$peopleAssociative = array("Alice"=>"17","Bob"=>"18");

$peopleMultiDimensional = array("Alice"=>array('C','Z'),"Bob"=>array('H','W','L'));

echo $peopleNumber[0]; // Alice

echo $peopleAssociative['Alice']; // 17

echo $peopleMultiDimensional['Bob'][2]; // L

// 循环

$intForWhile = 1;

while ($intForWhile<9) {

echo "Current: ".$intForWhile;

$intForWhile++;

}

do {

echo "Current: ".$intForWhile;

$intForWhile++;

} while($intForWhile<20)

for ($i = 0;$i <9;$i++) {

echo "Current: ".$i;

if ($i==7) {

continue;

}

foreach($peopleNumeric as $ $person) {

echo $person; // Alice Bob

}

// switch

switch ($peopleNumber[0]) {

case "Alice":

echo "Alice";

break;

case "bob":

case "Bob":

echo "Bob";

break;

default:

echo "No match";

}

// superglobals

echo $_SERVER['SCRIPT_NAME']; // including $GLOBALS, $_REQUEST, $_POST, $_GET, $_FILES, $_ENV, $_COOKIE, $_SESSION

echo $_SERVER['SCRIPT_FILENAME'];

echo $_SERVER['SCRIPT_URL'];

echo $_SERVER['HTTP_HOST'];

echo $_SERVER['PHP_SELF'];

echo $_SERVER['SERVER_ADDR'];

echo $_SERVER['SERVER_NAME'];

echo $_SERVER['SERVER_PORT'];

echo $_SERVER['REMOTE_ADDR'];

echo $_SERVER['REMOTE_HOST'];

echo $_SERVER['REMOTE_PORT'];

// 文件操作

$file=fopen("file.txt", "w"); // mode: r, w, a, x, r+, w+, a+, x+. a mode won't erase data

fwrite($file,"TEXT\n"); // the original content is erased

fclose($file); // return true or false

$file=fopen("file.txt", "a");

fwrite($file,"TEXT\n"); // content of the file: TEST\nTEST\n

fclose($file);

$content=file("file.txt");

$count=count($content); // get length of the array

foreach ($content as $line) {

echo $line."\n";

}

post.php 以 POST 方式提交表单

<html>
 <body>
  <form action="main.php" method="post"> // data sent to main.php when the page is submitted. if action is not set, data will be sent to the file itself
   <p>Name: <input type="text" name="name" /></p>
   <p><input type="submit" name="submit" value="Submit" /></p>
  </form>
 </body>
</html>

<html>

<body>

<form action="main.php" method="post"> // data sent to main.php when the page is submitted. if action is not set, data will be sent to the file itself

</form>

</body>

</html>

main.php 接收 POST

<html>
 <body>
Welcome <?
php echo $_POST["name"]; // for post method, which is preferred for sending (big) data 
?>
 </body>
</html>

<html>

<body>

Welcome <?

php echo $_POST["name"]; // for post method, which is preferred for sending (big) data

</body>

</html>

session_cookie_get.php 将数据存至 session 与 Cookie

<?php
 session_start();
 $_SESSION['temp']='TEST';
 setcookie("user", "Alice", time()+(86400*7), '/'); // must be used before <html> tag
 if (isset($_COOKIE['user'])) { // check if the value has been set
  echo $_COOKIE['user']." is set in cookie";
 }
?>
<html>
 <body>
  <form action="actionGet.php" method="get">
   <p>data included in URL, e.g., actionGet.php?name=Alice</p>
   <p>Name: <input type="text" name="name" /></p>
   <p><input type="submit" name="submit" value="Submit" /></p>
  </form>
 </body>
</html>

<?php

session_start();

$_SESSION['temp']='TEST';

setcookie("user", "Alice", time()+(86400*7), '/'); // must be used before <html> tag

if (isset($_COOKIE['user'])) { // check if the value has been set

echo $_COOKIE['user']." is set in cookie";

}

<html>

<body>

<p>data included in URL, e.g., actionGet.php?name=Alice</p>

</form>

</body>

</html>

actionGet.php 接收 GET

<html>
 <body>
Welcome <?php echo $_GET['name']; ?>
<?php
 echo $_SESSION['temp']; // TEST
 session_unset();
 session_destroy();
 if (isset($_GET['name'])) { 
  $file=fopen("names.txt", "a"); 
  fwrite($file, $_GET['name']); 
  fclose($file);
  echo $_COOKIE['user']." is set in cookie";
 }
?>
 </body>
</html>

<html>

<body>

Welcome <?php echo $_GET['name']; ?>

<?php

echo $_SESSION['temp']; // TEST

session_unset();

session_destroy();

if (isset($_GET['name'])) {

$file=fopen("names.txt", "a");

fwrite($file, $_GET['name']);

fclose($file);

echo $_COOKIE['user']." is set in cookie";

}

</body>

</html>

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