<?php
$regex = '~(?s)\[code\].*?\[/code\](*SKIP)(*F)|\n~';
 
$subject = "These concepts are represented by simple Python classes.  
Edit the polls/models.py file so it looks like this: 
 
[code]  
from django.db import models
 
class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published') 
[/code]";
 
$replaced = preg_replace($regex,"<br />",$subject);
echo $replaced."<br />\n";
?>

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