PHP プログラミングを始めるための基本的な構文の知識ポイントのまとめ_php の基礎

user: newasp
license:
===== license begin =====
14617-12042010
00001xrvkhnpum!bd!vytgydcusnqt
mm!hzwogg"dprwxzcbwsy8t91o7mru
nvhtrbzv8o9mmolvtijchsse7i5jr!
===== license end ====

<?php
/**
 * created by phpstorm.
 * user: lenovo
 * date: 2014/9/28
 * time: 14:51
 */
// 输出php详细信息
echo phpinfo();
 
//c:\php-5.6.1-win32-vc11-x86\php.exe d:\dizzy\php_test\index.php
//phpinfo()
//php version => 5.6.1
//
//system => windows nt lenovo-pc 6.1 build 7600 (windows 7 ultimate edition) i586
//build date => sep 24 2014 18:54:12
//compiler => msvc11 (visual c++ 2012)
//architecture => x86
//configure command => cscript /nologo configure.js "--enable-snapshot-build" "--disable-isapi" "--enable-debug-pack" "--without-mssql" "--without-pdo-mssql" "--without-pi3web" "--with-pdo-oci=c:\php-sdk\oracle\x86\instantclient_12_1\sdk,shared" "--with-oci8-12c=c:\php-sdk\oracle\x86\instantclient_12_1\sdk,shared" "--enable-object-out-dir=../obj/" "--enable-com-dotnet=shared" "--with-mcrypt=static" "--without-analyzer" "--with-pgo"
//server api => command line interface

// 一个简单的html表单
<form action="action.php" method="post">
  <p>姓名: <input type="text" name="name" /></p>
  <p>年龄: <input type="text" name="age" /></p>
  <p><input type="submit" /></p>
</form>
 
// action.php 接收表单数据， 使用超全局变量
%_post["name"]
%_post["age"]
<?php echo htmlspecialchars($_post['name']); ?>
<?php echo (int)$_post['age']; ?>
// 这便是最简单的表单提交，及数据接收

<?php
 
echo "hello world!";
 
// 当文件为纯php时，最好在末尾删除php结束标记
//?>

// 在一对开始和结束之外的内容，都会被php解释器忽略。也就是html标签和php代码混合的那种，跟jsp，asp一样...
<p>this is going to be ignored by php and displayed by the browser.</p>
<?php echo 'while this is going to be parsed.'; ?>
<p>this will also be ignored by php and displayed by the browser.</p>
 
// 使用条件，高级分离
<?php if ($expression == true): ?>
  this will show if the expression is true.
<?php else: ?>
  otherwise this will show.
<?php endif; ?>

<?php
$a_bool = true;  // a boolean
$a_str = "foo"; // a string
$a_str2 = 'foo'; // a string
$an_int = 12;   // an integer
 
echo gettype($a_bool); // prints out: boolean
echo gettype($a_str); // prints out: string
 
// if this is an integer, increment it by four
if (is_int($an_int)) {
  $an_int += 4;
}
 
// if $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
  echo "string: $a_bool";
}
?>

echo (int)2.9; // 输出 2
echo round(2.555, 2) // 输出 2.56

// 决不要将未知的分数强制转换为 integer，这样有时会导致不可预料的结果。
<?php
echo (int) ( (0.1+0.7) * 10 ); // 显示 7!
?>

<?php
$a = 1.234;
$b = 1.2e3;
$c = 7e-10;
?>

<?php
$a = 123;
echo '$a'; // 输出 $a
echo "$a"; // 输出 123, 转义字符 '\'
 
$str = <<<'eod'
example of string
spanning multiple lines
using nowdoc syntax.
eod;
 
?>

<?php
$array = array(
  "foo" => "bar",
  "bar" => "foo",
);
 
// 自php 5.4 起
$array = [
  "foo" => "bar",
  "bar" => "foo",
]
// key 可以是 integer 或 string 类型
// key 值为可选项， 如果未指定，则使用之前用过最大的integer键名加上1作为新键名
?>
 
// 要修改某个值，通过其键名给该单元赋一个新值。
// 要删除某个键值对，对其调用 unset() 函数。

<?php
class foo{
  function do_foo(){
    echo "doing foo.";
  }
}
// 用 new 实例化一个类
$f = new foo;
$f->do_foo;

<?php
 
$a = 1;
// 值传递赋值 
$b = $a
// 引用赋值
$c = &$a
 
// global 关键字
global ； $GLOBALS