Why are PHP array values ​​not displayed? How to deal with it?

In PHP, an array is a data type that stores multiple values. If your PHP array values ​​are not displaying, there could be a few reasons:

1. Array variables are not defined correctly
   If you do not define array variables correctly before displaying the array values, then the Array values ​​will not be displayed. Please make sure you use the correct syntax to define variables. For example:

   $arr = array('apple', 'orange', 'banana');

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2. Accidental reset of array pointer
   If you accidentally reset the array pointer while working with an array, the array value will not be displayed. When working with arrays, make sure you know the pointer position you are operating on. For example:

   $arr = array('apple', 'orange', 'banana');
   reset($arr); // 重置数组指针
   while (list(, $val) = each($arr)) {
     echo "$val\n";
   }

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3. Array value is empty
   If your array value is empty, then the value will not be displayed. You can use the isset() function to check whether an array value exists. For example:

   $arr = array('apple', '', 'banana');
   for ($i = 0; $i < count($arr); $i++) {
     if (isset($arr[$i]) && $arr[$i] != '') {
       echo $arr[$i] . "\n";
     }
   }

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4. Not outputting the array value correctly
   Finally, you may not be outputting the array value correctly. Please make sure you use the correct syntax when displaying array values. For example:

   $arr = array('apple', 'orange', 'banana');
   foreach ($arr as $val) {
     echo $val . "\n";
   }

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In summary, if your PHP array values ​​are not displayed, please check the above reasons and fix them with appropriate workarounds.

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