基于键值取消设置数组[关闭]答案

【问题标题】：Unset Array based on key value [closed]基于键值取消设置数组[关闭]
【发布时间】：2021-12-28 06:08:00
【问题描述】：

我这里有这个数组，我们称之为$_products，我的目标是根据“activationdate”的键值删除数组，如果它大于今天的日期。

{
    "id": "1388",
    "name": "June 2019 -  2014 Kate Hill & 2014 Pressing Matters",
    "image": "linkurl",
    "month": "June 2019",
    "activationdate": "2019-06-01",
    "wine1": "2014 Kate Hill Pinot Noir",
    "wine2": "2014 Pressing Matters Pinot Noir"
},

{   //I WANT TO REMOVE THIS ARRAY
    "id": "8421",
    "name": "December 2021 Releases: Apsley Gorge Pinot Noir 2018 $65 & Milton Pinot Noir 2019 $38",
    "image": "linkurl",
    "month": "December 2021",
    "activationdate": "2021-12-03",
    "wine1": "Apsley Gorge Pinot Noir 2018",
    "wine2": "Milton Pinot Noir 2019"
}

所以对于我的 PHP 循环

$date_now = date('Y-m-d'); //get today's date with format e.g 2021-01-02
foreach( $_products as $month => $_product ) {

if( $_product['activationdate'] > $date_now  )
   unset($_products[$month]);
}

但是，它并没有取消设置数组？

【问题讨论】：

您正在将日期与字符串进行比较。 $_product['activationdate'] > $date_now
嗯，奇怪。我确实尝试将两者与真/假进行比较。它回显了“真”，但没有删除数组。有什么建议吗？
您能否确认您有 JSON 提要并使用 json_decode 将其转换为数组？
先设置item为null，然后循环后，用户array_filter删除空值
离题：无法重现。

标签： php loops foreach unset

【解决方案1】：

像这样使用foreach：

foreach($_products as $k=>$v ) 

if( $v->activationdate>$date_now) unset($_products[$k]);

您在foreach 中使用了month，但这也是关键，具有误导性。

整个代码：

<?php

$s = '[
{
    "id": "1388",
    "name": "June 2019 -  2014 Kate Hill & 2014 Pressing Matters",
    "image": "linkurl",
    "month": "June 2019",
    "activationdate": "2019-06-01",
    "wine1": "2014 Kate Hill Pinot Noir",
    "wine2": "2014 Pressing Matters Pinot Noir"
},
{
    "id": "8421",
    "name": "December 2021 Releases: Apsley Gorge Pinot Noir 2018 $65 & Milton Pinot Noir 2019 $38",
    "image": "linkurl",
    "month": "December 2021",
    "activationdate": "2021-12-03",
    "wine1": "Apsley Gorge Pinot Noir 2018",
    "wine2": "Milton Pinot Noir 2019"
}
]';

$p=json_decode($s);

$date_now = date('Y-m-d'); //get today's date with format e.g 2021-01-02

foreach($p as $k=>$v ) if( $v->activationdate>$date_now) unset($p[$k]);

var_dump( $p);
?>

Teh playground

【讨论】：

【解决方案2】：

好的，我假设您有 JSON 提要，例如 $product_feed，如下所示

$json = $json = '[
{
    "id": "1388",
    "name": "June 2019 -  2014 Kate Hill & 2014 Pressing Matters",
    "image": "linkurl",
    "month": "June 2019",
    "activationdate": "2019-06-01",
    "wine1": "2014 Kate Hill Pinot Noir",
    "wine2": "2014 Pressing Matters Pinot Noir"
},
{
    "id": "8421",
    "name": "December 2021 Releases: Apsley Gorge Pinot Noir 2018 $65 & Milton Pinot Noir 2019 $38",
    "image": "linkurl",
    "month": "December 2021",
    "activationdate": "2021-12-03",
    "wine1": "Apsley Gorge Pinot Noir 2018",
    "wine2": "Milton Pinot Noir 2019"
}
]';

我已经使用 json_decode 函数将其转换为 PHP 数组

$products = json_decode($json);

下一步为了与当前日期进行比较，我已将当前日期转换为时间字符串，如下所示

$current_date = strtotime(date('Y-m-d'));

主循环和取消设置任务如下

foreach ($products as $month => $product) {
    if(strtotime($product->activationdate) > $current_date) { // Date comparison
        unset($products[$month]); // Here you made a mistake
    }
}

在这种情况下，您正在尝试取消设置您应该使用该键取消设置数组元素的键。

数组删除前后打印的完整代码如下：

$json = '[
    {
        "id": "1388",
        "name": "June 2019 -  2014 Kate Hill & 2014 Pressing Matters",
        "image": "linkurl",
        "month": "June 2019",
        "activationdate": "2019-06-01",
        "wine1": "2014 Kate Hill Pinot Noir",
        "wine2": "2014 Pressing Matters Pinot Noir"
    },
    {
        "id": "8421",
        "name": "December 2021 Releases: Apsley Gorge Pinot Noir 2018 $65 & Milton Pinot Noir 2019 $38",
        "image": "linkurl",
        "month": "December 2021",
        "activationdate": "2021-12-03",
        "wine1": "Apsley Gorge Pinot Noir 2018",
        "wine2": "Milton Pinot Noir 2019"
    }
]';
$products = json_decode($json);
$current_date = strtotime(date('Y-m-d'));
print_r($products);
foreach ($products as $month => $product) {
    if(strtotime($product->activationdate) > $current_date) { // Date comparison
        unset($products[$month]); // Here you made a mistake
    }
}
print_r($products);

print_r 的输出是

Array
(
    [0] => stdClass Object
        (
            [id] => 1388
            [name] => June 2019 -  2014 Kate Hill & 2014 Pressing Matters
            [image] => linkurl
            [month] => June 2019
            [activationdate] => 2019-06-01
            [wine1] => 2014 Kate Hill Pinot Noir
            [wine2] => 2014 Pressing Matters Pinot Noir
        )

    [1] => stdClass Object
        (
            [id] => 8421
            [name] => December 2021 Releases: Apsley Gorge Pinot Noir 2018 $65 & Milton Pinot Noir 2019 $38
            [image] => linkurl
            [month] => December 2021
            [activationdate] => 2021-12-03
            [wine1] => Apsley Gorge Pinot Noir 2018
            [wine2] => Milton Pinot Noir 2019
        )

)
Array
(
    [0] => stdClass Object
        (
            [id] => 1388
            [name] => June 2019 -  2014 Kate Hill & 2014 Pressing Matters
            [image] => linkurl
            [month] => June 2019
            [activationdate] => 2019-06-01
            [wine1] => 2014 Kate Hill Pinot Noir
            [wine2] => 2014 Pressing Matters Pinot Noir
        )

)

我希望这就是您想要的！干杯！

你可以玩转代码here

【讨论】：

strtotime() 不是必需的。
感谢您创建此@Vantiya，但不幸的是，我仍然无法使其工作：/
@ccmanz 试试这个 $date_now = strtotime(date('Y-m-d'));而不是 $date_now = date('Y-m-d');并在循环中使用相同的 if 条件，例如 if( strtotime($_product['activationdate']) > $date_now ) 实际上，两个日期都应转换为 unix 时间戳进行比较。我确信您的代码中的条件不匹配，因此未执行未发送。

【解决方案3】：

您在循环中使用了不正确的变量。

替换

unset($_products[$month]);

与

unset($_product[$month]);

【讨论】：

我确实更新了这个 if( $_product['activationdate'] > $date_now ) unset( $_product[$month] );它仍然没有删除数组。如果我将值与真/假进行比较，则结果为真，但不会删除数组。
所以这个页面应该作为错字关闭而不是回答？
@ccmanz，在循环中创建一个新数组，然后将字段放入该数组并检查新输出
@mickmackusa 虽然我犯了一个拼写错误。我仍然无法让它工作。我的道歉
@VishalParkash 我会试试的