Help with understanding Code

[dcampbell18]

Hello! Can someone please help me to understand this section of code?  It works correctly, but I don't fully understand how it works, which is preventing me from moving further in my program.  Here is the code:

 

if(!empty($_POST['color']) && is_array($_POST['color'])) {
$_POST['color'] = array_map('mysql_real_escape_string', $_POST['color']);
$colors = implode('\'), (\'', $_POST['color']);

           
$query = 'INSERT INTO colors (color) VALUES (\'' . $colors . '\')';
$rs = mysql_query($query);


} else {
// they didn't specify a color, or there was a problem with the data type 
}

 

I understand this much:  If "color" is checked (true) and it's an array, then insert the value of "color" into the database table named "colors".  Else, do nothing.  This will insert the data each in a separate row in my table which is exactly what I want it to do.  Here are my specific questions: 

 

1.  What does 'array_map' and 'mysql_real_escape_string' do? 

2.  What does the '\' do in the line:  $colors = implode('\'), (\'', $_POST['color']);

3.  What does the '\' do in the line:  $query = 'INSERT INTO colors (color) VALUES (\'' . $colors . '\')';

 

Thank you in advance for any explanation you can give me! 

[trq]

1. array_map will call the function named in its first argument (in this case mysql_real_escape_string) on each element of the array in its second.

 

2. That doesn't look at all valid to me.

 

3. Backslashes escape the next following char within a string.

[kenrbnsn]

A more understandable way to write these two lines:

<?php
$colors = implode('\'), (\'', $_POST['color']);
      	$query = 'INSERT INTO colors (color) VALUES (\'' . $colors . '\')';
?>

would be to use double quotes to delimit the strings instead of single quotes:

<?php
$colors = implode("'), ('", $_POST['color']);
$query = "INSERT INTO colors (color) VALUES ('" . $colors . "')";
?>

 

Ken

 

[trq]

Actually, looking at question 2. It looks like it may be valid. explode splits a string (by the first argument) into an array.

 

So if you had...

 

<?php

 $str = 'foo,bar,bob';
 $arr = explode(',',$str);
 // you'd end up with.
 echo $arr[0]; // foo
 echo $arr[1]; // bar
 echo $arr[2]; // bob

?>

 

Given your code it would split the string contained in $_POST['color'] on '), ('