Re: Newbie Question about Conditionals

On Tue, Mar 30, 2010 at 9:22 PM, Matty Sarro <msarro@gmail.com> wrote: > Hey all! > This is probably my second post on the list, so please be gentle. Right now > I am running through the "Heads First PHP and MySQL" book from O'Reilly. > It's been quite enjoyable so far, but I have some questions about some of > the code they're using in one of the chapters. > > Basically the code is retreiving rows from a DB, and I'm just not getting > the explanation of how it works. > > Here's the code: > > $result=mysqli_query($dbc,$query) > > while($row=mysqli_fetch_array($result)){ > echo $row['first_name'].' '.$row['last_name'].' : '. > $row['email'] . '<br > />'; > } > > Now, I know what it does, but I don't understand how the conditional > statement in the while loop works. Isn't an assignment operation always > going to result in a "true" condition? Even if mysqli_fetch_array($result) > returned empty values (or null) wouldn't the actual assignment to $row still > be considered a true statement? I would have sworn that assignment > operations ALWAYS equated to true if used in conditional operations. > Please help explain! :) > > Thanks so much! > -Matty > http://www.php.net/manual/en/function.mysql-fetch-array.php "Returns an array of strings that corresponds to the fetched row, or FALSE if there are no more rows." while($row=mysqli_fetch_array($result)) is equivalent to this: $row=mysqli_fetch_array($result); while ($row){ // do something $row=mysqli_fetch_array($result); } So, if $row is not equal to FALSE, the loop will happens.