How can debugging techniques like print_r() and mysql_error() help identify issues in PHP code?

Debugging techniques like print_r() and mysql_error() can help identify issues in PHP code by providing more information about what is happening in the code at runtime. print_r() can be used to print out the contents of variables, arrays, and objects, allowing you to see the values and structures of your data. mysql_error() can be used to display any errors that may occur during a MySQL query, helping you pinpoint where the issue is in your database interactions. 

// Example code using print_r() to debug an array
$array = [1, 2, 3];
print_r($array);
```

```php
// Example code using mysql_error() to debug a MySQL query
$query = "SELECT * FROM users WHERE id = 'abc'";
$result = mysql_query($query);
if (!$result) {
    die('Invalid query: ' . mysql_error());
}

Keywords

print_r mysql_error debugging techniques PHP code identify issues

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