PHP foreach loop =>

Question

So I've been researching into PHP to create a basic email form and I came across some code which I decided I would take a look at and experiment with.

The HTML form I am working with is:

<form method="post" action="newsjoin.php"> 

<table align=center> 
<tr>
  <td><select name="sendto" hidden="hidden"> <option value="newsletter@myDomain.com" selected="selected">Newsletter</option> </select></td>
</tr> 
<tr>
  <td><font color=red>*</font> Name:</td>
  <td><input size=25 name="Name"></td>
</tr> 
<tr>
  <td><font color=red>*</font> Email:</td>
  <td><input size=25 name="Email"></td>
</tr>
<tr>
  <td><input type="radio" name="list" value="No" hidden="hidden" /> <input type="radio" name="list" value="Yes" hidden="hidden" checked="checked" /></td>
</tr>
<tr>
  <td colspan=2 align=left><input type=submit name="send" value="Submit"></td>
</tr> 
<tr>
  <td><br /></td>
</tr>
<tr>
  <td colspan=2 align=left><small>A <font color=red>*</font> indicates a field is required</small></td>
</tr> 
</table> 

</form> 

And my newsjoin.php file contains:

<?php 
$to = $_REQUEST['sendto'] ; 
$from = $_REQUEST['Email'] ; 
$name = $_REQUEST['Name'] ; 
$headers = "From: $from"; 
$subject = "Web Contact Data"; 

$fields = array(); 
$fields{"Name"} = "Name";
$fields{"Email"} = "Email";
$fields{"list"} = "Mailing List";

$body = "We have received the following information:\n\n"; foreach($fields as $a => $b){ $body .= sprintf("%20s: %s\n",$b,$_REQUEST[$a]); } 

$headers2 = "From: newsletter@myDomain.com"; 
$subject2 = "Thank you for contacting us"; 
$autoreply = "Thank you for subscribing to our mailing list. You should recieve another email shortly confirming our reciept of this information.";

if($from == '') {
    print "You have not entered an email, please go back and try again.";
} 
else { 
    if($name == '') {
        print "You have not entered a name, please go back and try again.";
    } 
    else { 
        $send = mail($to, $subject, $body, $headers);       // this is the mail to site staff
        $send2 = mail($from, $subject2, $autoreply, $headers2);     // this is the mail to the user
        if($send) {
            header( "Location: http://www.myDomain.com/newsletter_joined.html" );
        } 
        else {
            print "We encountered an error sending your mail, please notify admin@myDomain.com"; 
        } 
    }
}
?> 

Now, this all looks ok to me except for I don't understand this line:

$body = "We have received the following information:\n\n"; foreach($fields as $a => $b){ $body .= sprintf("%20s: %s\n",$b,$_REQUEST[$a]); } 

Namely, I do not understand the $a => $b section, nor do I understand the use of these variables(if they are variables) in the sprint() function.

I have spent the past 4 hours on Google trying to learn what I can about php being used this way and had no luck.

Thanks!

Answer 1

That is a key-value-pair enumeration. Basically, it's iterating over the collection $fields and at each iteration, it binds the variable $a to the key, and the variable $b to the value.

  foreach($fields as $a => $b)
  {
      // iterates over all key-value pairs in the collection $fields
      //   at each iteration (for each key-value pair in the collection)
      //   $a is bound to the key
      //   $b is bound to the value
  }

If you had an associative array like this:

  $collection = array(1 => 'one', 2 => 'two', 3 => 'three');

Then the following loop would print: 1: one; 2: two; 3: three;

  foreach($collection as $key => $value)
  {
      echo $key.': '.$value.'; ';
  }

---

nor do I understand the use of these variables(if they are variables) in the sprint() function.

For the second part of your question, the sprintf function essentially generates a formatted string based on the format pattern, and the variables given. So:

sprintf("%20s: %s\n", $b, $_REQUEST[$a]);
           ^           ^     ^
           |           |     +--- second variable parameter
           |           |                                |
           |           +---- first variable parameter   |
           |                                       |    |
           |                                       V    V
           +----------- string format            "%20s: %s\n"

returns a formatted string that outputs a:

• right-justified, space padded, fixed width (20 character) string representation of the first parameter (variable $b which as explained above is the value in the key-value enumeration),

• followed by colon,

• followed by a space, and then

• followed by the string representation of the second parameter ($_REQUEST[$a] which is a value from the $_REQUEST array, indexed by the value of the variable $a, which again, as explained above, is bound to the key in the key-value pair enumeration)