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12月02日 - PHP基础知识复习
SmileHoHo
Original
557 people have browsed it

PHP基础知识复习

代码区

  1. <?php
  2. //数据,变量表示,放在数据段
  3. $site = '北京';
  4. //代码,函数表示,放在代码段
  5. function get_site($website){
  6. return $website . '欢迎您!';
  7. }
  8. //调用执行。
  9. echo get_site($site);
  10. echo '<hr>';
  11. //变量名是name,变量值的类型是字符串
  12. $name = 'Miss Zhu';
  13. $age = 18;
  14. $isMarried = true;
  15. //单值读取 echo:回显,无返回值
  16. echo '名字:'. $name . '<br>年龄:' . $age . '<br>婚否:' . $isMarried;
  17. echo '<hr>';
  18. //字符串虽是单值,也可以像数组一样访问
  19. echo '第五个字母是:' . $name{5};
  20. echo '<hr>';
  21. //print: 打印, 与echo功能类似 , 但是会有返回值: 1
  22. print('年龄:' . $age . '<br>');
  23. echo print('年龄:' . $age . '<br>');
  24. echo '<hr>';
  25. // print_r($var, false|true)
  26. print_r($name);
  27. echo '<hr>';
  28. echo print_r($name, true);
  29. echo '<hr>';
  30. //从1-20,间隔3
  31. $data = range(1,20,3);
  32. echo '<pre>'.print_r($data,true).'</pre>';
  33. echo '<hr>';
  34. var_export($name);
  35. echo '<hr>';
  36. var_dump($name, $age, $isMarried);

  1. <?php
  2. //索引数组
  3. //1. 定义 直接定义
  4. $user[] = 101;
  5. $user[] = 'admin';
  6. $user[] = 'admin@qq.com';
  7. //推荐方式
  8. $user = [101,'admin','admin@qq.com'];
  9. //2.访问: 单个或多个成员
  10. echo $user[2]. '<br>';
  11. print_r($user);
  12. echo '<pre>'.print_r($user,true).'</pre>';
  13. var_dump($user);
  14. echo '<hr>';
  15. //3. 遍历: 可循环访问全部成员
  16. //for: 索引数组,最常用的是for循环
  17. $res = '';
  18. for($i = 0;$i < count($user); $i++) {
  19. $res .=$user[$i] .' , ';
  20. }
  21. // 去掉最后的', ', 输出遍历结果
  22. echo rtrim($res, ', ');
  23. echo '<hr>';
  24. //foreach
  25. $res = '';
  26. foreach ($user as $v){
  27. $res .= $v.', ';
  28. }
  29. echo rtrim($res,', ');
  30. echo '<hr>';
  31. //转换
  32. list($id, $name, $email) = $user;
  33. echo $id . '-' . $name . '-' . $email . '<hr>';
  34. $str = implode(',', $user);
  35. echo $str, '<br>';
  36. $sql = "INSERT `users` SET `comment` = {$str};";
  37. echo '<hr>';
  38. $arr = explode(',', $str);
  39. print_r($arr);
  40. echo '<hr>';
  41. while (list($key, $value) = each($user)) {
  42. echo '[' . $key . '] => ' . $value . '<br>';
  43. }
  44. echo '<hr>';
  45. echo '<hr>';
  46. // 关联数组
  47. $user = ['id'=>101, 'name'=>'admin', 'email'=>'admin@php.cn'];
  48. // 访问
  49. echo $user['email'] . '<br>';
  50. print_r($user);
  51. var_dump($user);
  52. var_export($user);
  53. echo '<hr>';
  54. //遍历
  55. //foreach: 推荐
  56. foreach ($user as $key=>$value) {
  57. echo '[' . $key . '] => ' . $value . '<br>';
  58. }
  59. //for: 并不适合关联数组,但是借助数组指针, 也可以完成遍历
  60. $res = '';
  61. for ($i = 0; $i < count($user); $i++) {
  62. $res .= current($user) . ', ';
  63. next($user);
  64. }
  65. echo rtrim($res, ', ');
  66. echo '<hr>';
  67. //转换
  68. extract($user);
  69. echo 'id = ' . $id . ', name = ' . $name . ', email = ' . $email . '<br>';
  70. $dsn = 'mysql:host=localhost;dbname=demo';
  71. $username = 'root';
  72. $password = 'root';
  73. $linkParams = compact('dsn', 'username', 'password');
  74. print_r($linkParams);
  75. echo '<br>';
  76. // 关联数组转索引数组
  77. print_r(array_values($user));



手抄作业:








Correcting teacher:天蓬老师天蓬老师

Correction status:qualified

Teacher's comments:字写得比老师好看多了, 相信你把这个复习笔记抄写完, 对编程应该有了一个整体上的认识, 明白了许多底层原理, 这对以后编程非常有帮助的
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