8.16.1. Problem

8.16.2. Solution

error_reporting(E_ALL);                // everything
error_reporting(E_ERROR | E_PARSE);    // only major problems
error_reporting(E_ALL & ~E_NOTICE);    // everything but notices

8.16.3. Discussion

// Generates an E_NOTICE
foreach ($array as $value) {
    $html .= $value;
}

// Doesn't generate any error message
$html = '';
foreach ($array as $value) {
    $html .= $value;
}

In the first case, the first time though the foreach, $html is undefined. So, when you append to it, PHP lets you know you're appending to an undefined variable. In the second case, the empty string is assigned to $html above the loop to avoid the E_NOTICE. The previous two code snippets generate identical code because the default value of a variable is the empty string. The E_NOTICE can be helpful because, for example, you may have misspelled a variable name:

foreach ($array as $value) {
    $hmtl .= $value; // oops! that should be $html
}

$html = ''
foreach ($array as $value) {
    $hmtl .= $value; // oops! that should be $html
}

Table 8-2. Error types

8.16.4. See Also