PHP error handling function user_error()

Last update on May 28 2022 12:33:53 (UTC/GMT +8 hours)

Description

PHP function user_error() generates a user-level error or warning or notice.

The function can be used either along with the built-in error handler or with a user defined function which is set as the new error handler (set_error_handler()).

If you want to generate a specific response to an exception at runtime, using this function is useful.

This function is an alias of trigger_error().

Version:

PHP 4, PHP 5.

Syntax:

trigger_error(error_msg,  error_type )

Parameter:

Parameters	Description	Required / Optional	Type
error_msg	A string which will be displayed as an error message.	Required	string
error_type	Specifies the error type for an error message. Values may be - 1. E_USER_ERROR. 2. E_USER_WARNING. 3. E_USER_NOTICE.	Optional	integer

Return Values:

The function returns FALSE if the wrong error_type is specified. Otherwise, it returns TRUE.

Example:

<?php
  $a = 12;
    $b = 5;
    
  if($a%$b == 0)
  trigger_error("This is an error",E_USER_NOTICE );
  ?>

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC