Php key is undefined, but there is key

Question

I am making my own array from another one, using email field as key value. If there is more results with same email I am amking public ionViewWillEnter(): void { this.appNav.swipeBackEnabled = true; } public ionViewDidLeave(): void { this.appNav.swipeBackEnabled = false; } to existing key.

I am getting always data in my array (with email) and here is the example

Input data

Example data

array_push

Code

$saved_data = [
    0 => ['custom_product_email' => 'test@test.com',...],
    1 => ['custom_product_email' => 'test@test.com',...],
    2 => ['custom_product_email' => 'bla@test.com',...],
    3 => ['custom_product_email' => 'bla@test.com',...],
    ...
];

Error

I am getting error $data = []; foreach ($saved_data as $products) { $curVal = $data[$products->custom_product_email]; if (!isset($curVal)) { $data[$products->custom_product_email] = []; } array_push($data[$products->custom_product_email], $products); } and if I debug my array, there is key with value of Undefined index: test@test.com, so key is defined (!)

so 'test@test.com' key is var $curVal

Result

So the goal of foreach is to filter all objects in array with same email, here is the example:

undefined

Answer 1

您没有看到错误消息吗？

  

解析错误：语法错误，意外＆＃39; {＆＃39;在.....从这段代码

$saved_data = [
    0 => {'custom_product_email' => 'test@test.com',...},
    1 => {'custom_product_email' => 'test@test.com',...},
    2 => {'custom_product_email' => 'bla@test.com',...},
    3 => {'custom_product_email' => 'bla@test.com',...},
    ...
];

将{}更改为[]以正确生成数组。

$saved_data = [
    0 => ['custom_product_email' => 'test@test.com',...],
    1 => ['custom_product_email' => 'test@test.com',...],
    2 => ['custom_product_email' => 'bla@test.com',...],
    3 => ['custom_product_email' => 'bla@test.com',...],
    ...
];

您的下一个问题在此代码中

$data = [];
foreach ($saved_data as $products) {
  $curVal = $data[$products->custom_product_email];
//          ^^^^^

$data是一个空数组，您在上面初始化了2行，因此它不包含任何键或数据！

Answer 2

这一行$curVal = $data[$products->custom_product_email];没用，是引发错误的行：你刚刚将$ data初始化为空数组，逻辑上索引是未定义的。

您应该直接测试if (!isset($data[$products->custom_product_email])) {

然后解释：在未定义的数组索引的值和isset中的相同代码之间存在根本区别。后者评估变量的存在，你可以放入一些不存在的东西（比如未定义的数组索引访问）。但是在测试之前你不能将它存储在一个变量中。

Answer 3

检查$data[$products->custom_product_email]数组

中是否已设置$data

尝试此代码

$data = [];

foreach ($saved_data as $products) {
  $curVal = isset($data[$products->custom_product_email]) ? $data[$products->custom_product_email] : null;
  if (!isset($curVal)) {
    $data[$products->custom_product_email] = [];
  }
  array_push($data[$products->custom_product_email], $products);
}