What does the - operator do in PHP?

Question

I was looking at an examples on using flashbuilder & mysql and i'm pretty new to php and found the following example, I was wondering what does -> do I haven't encountered it before i'm guessing it's some kind of assignment operator.


public function getAllEmployees($q) {		
 
    $sql = "SELECT * FROM $this->tablename WHERE first_name LIKE '%$q%' OR last_name LIKE '%$q%' OR email_address LIKE '%$q%'";
 
    $stmt = mysqli_prepare($this->connection,$sql);
 
    $this->throwExceptionOnError();
 
    mysqli_stmt_execute($stmt);
    $this->throwExceptionOnError();
 
    $rows = array();
 
    mysqli_stmt_bind_result($stmt, $row->emp_no, $row->birth_date, $row->first_name, $row->last_name, $row->gender, $row->hire_date, $row->phone_no, $row->email_address, $row->job_title);
 
    while (mysqli_stmt_fetch($stmt)) {
      $rows[] = $row;
      $row = new stdClass();
      mysqli_stmt_bind_result($stmt, $row->emp_no, $row->birth_date, $row->first_name, $row->last_name, $row->gender, $row->hire_date, $row->phone_no, $row->email_address, $row->job_title);
    }
 
    mysqli_stmt_free_result($stmt);
    mysqli_close($this->connection);
 
    return $rows;
}

The example was from http://www.flashrealtime.com/flash-builder-4-and-php-data-services/

just &quot;JR&quot; · Accepted Answer

The -> is not an assignment operator, but an "index-of", used from a class.
Here:
$row = new stdClass(); // a totally useless "class" that defines the contents of a table or similar.
That "class", called "$row" is an array that contains "emp_no", "birth_date", "first_name" etc
mysqli_stmt_bind_result($stmt, $row->emp_no, $row->birth_date, $row->first_name, ...);
Why using a class when you don't need it?
$sql = "select * .... ";
$res = mysql_query($sql);
while ($row = mysql_fetch_array($res))
{
echo ($row['emp_no'] . ", " . $row['birth_date'] ... );
}
The difference? >5 times faster.

Not to confuse with the "=>" operator, as used to link "key" with "value":
foreach ($row as $key => $value) where $row is an associative array, such as:
[0] => "Mon"
[1] => "Tue"
[2] => "Wed".

leonor · Answer

The "->" operator signifies a function within a class. In this case $doc is the class. Some where within the code there will probably be a line that looks similiar to this: $doc = new doc; That initiates the category and commits it to the variable $doc. When you wish to have to use any of the functions within the class doc, you could make the decision like this: $books = $doc->getElementsByTagName( "e-book" ); This tells the compiler that "getElementsByTagName" is a function with within the $doc class, and then appears to that category to execute the function. Eric

Preecher · Answer

have fun

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What does the -> operator do in PHP?

3 Answers