php 语法 – local global

php 语法 – local global

卡了我好久, 他妹的!

CREATE TABLE test.tes (
one varchar(20),
two varchar(20),
three varchar(20)
);

function insert($table, $arr) {
    $link = new mysqli (‘localhost‘, ‘root‘, ‘‘, ‘test‘) or die (‘connnect‘.$link->error);
    $key = array_keys($arr);
    $key = join(‘,‘, $key);
    // echo $key, ‘<br>‘;

    $value = array_values($arr);
    $value = "‘".join("‘,‘", $value)."‘";
    // echo $value, ‘<br>‘;

    $query = ‘insert into ‘.$table.‘ (‘.$key.‘) values (‘.$value.‘)‘;
    $link->query($query) or die (‘query fail: ‘.$link->error);
}

$arr = array(‘one‘=>‘1‘, ‘two‘=>‘2‘, ‘three‘=>‘3‘);
insert(‘test‘, $arr);

把 link 放在外面, 一直插入失败……

<?php
$link = new mysqli (‘localhost‘, ‘root‘, ‘‘, ‘test‘) or die (‘connnect‘.$link->error);

function insert($table, $arr) {
    $key = array_keys($arr);
    $key = join(‘,‘, $key);
    // echo $key, ‘<br>‘;

    $value = array_values($arr);
    $value = "‘".join("‘,‘", $value)."‘";
    // echo $value, ‘<br>‘;

    $query = ‘insert into ‘.$table.‘ (‘.$key.‘) values (‘.$value.‘)‘;
    $link->query($query) or die (‘query fail: ‘.$link->error);
}

$arr = array(‘one‘=>‘1‘, ‘two‘=>‘2‘, ‘three‘=>‘3‘);
insert(‘test‘, $arr);
?>

现在成功了, 靠

<?php
$link = new mysqli (‘localhost‘, ‘root‘, ‘‘, ‘test‘) or die (‘connnect‘.$link->error);

function insert($table, $arr) {
    global $link;

    $key = array_keys($arr);
    $key = join(‘,‘, $key);
    // echo $key, ‘<br>‘;

    $value = array_values($arr);
    $value = "‘".join("‘,‘", $value)."‘";
    // echo $value, ‘<br>‘;

    $query = ‘insert into ‘.$table.‘ (‘.$key.‘) values (‘.$value.‘)‘;
    $link->query($query) or die (‘query fail: ‘.$link->error);
}

$arr = array(‘one‘=>‘1‘, ‘two‘=>‘2‘, ‘three‘=>‘3‘);
insert(‘test‘, $arr);
?>

总结, 函数里面, 要想引用外部的变量, 要先用 global $... 引入

$a = 3;
function f() {
    global $a;     // 没有 global 会出错
    echo $a;
}
f();

function f() {
    global $a;
    $a = 3;
}

f();
echo $a;          // 3