foreach循环中的PHP'非法字符串偏移'

Question

I am getting an assoc array from a MySQL database using PDO.

I want to perform a function on it to trim down the number of words by using the following code:

$newsContent = Words::truncateWords($rows);

I am getting this error and the the function hasn't worked

Warning: Illegal string offset 'content' in C:\www\mvc\libs\Words.php on line 14

Notice: Uninitialized string offset: 0 in C:\www\mvc\libs\Words.php on line 14

Warning: Illegal string offset 'content' in C:\www\mvc\libs\Words.php on line 14

The first error is repeated about 8 times. Line 14 points to this line

$rows[$key]['content'] = self::trunc($row['content'], 60);

Here is my Words class

class Words {

    // truncate each of the news item's content to a set number of words
    public static function truncateWords($rows) {

        // loop through the array 
        foreach($rows as $key => $row) {
            // and truncate content to 60 words
            $rows[$key]['content'] = self::trunc($row['content'], 60);
        }

        return $rows;
    }

    public function trunc($phrase, $max_words)
    {
        $phrase_array = explode(' ',$phrase);

        if(count($phrase_array) > $max_words && $max_words > 0)
            $phrase = implode(' ',array_slice($phrase_array, 0, $max_words)).'...';

        return $phrase;
    }
}

Answer 1

This is because content is not a subscript of $row Check first and see if it is.

array_key_exists checks if the variable is set, but it does not check that variable is NOT null

if(array_key_exists('content', $row) {
   self::trunc($row['content'], 60);
}

To check that the subscript exists and is not null, use isset