PHP - Help With String Replacing?

I want to be able to replace, let's say, every fifth letter from a string.

The string is unknown, though, it could come from database, or a POST form. So I'm unsure if I could use str_replace.

I think I may need to use preg_replace(), but I'm not not sure.

I'm having an issue with users uploading files with a Semi Colon in the file name.
I am currently using a script that replaces characters within the file name, however, when I try to add a ";" as invalid characters to replace, it is like the semi-colon just stops the script, as the file does not upload (no errors are displayed).

Here's the code I'm working with:


$valid_chars_regex = '.A-Z0-9_ !@#$%^&()+={}\[\],~`-';
$file_name = preg_replace('/[^'.$valid_chars_regex.']|\'.+$/i', "", basename($_FILES[$upload_name]['name']));
if (strlen($file_name) == 0 || strlen($file_name) > $MAX_FILENAME_LENGTH) {
HandleError("Invalid file name");
exit(0);
}


I tried placing the semi colon all over the place in the preg_replace function, but nothing seems to work.

How can I do this?

Hi

I am trying to replace characters in a string with images so character 'a' will be replaced with a.jpg etc  I have tried the following code but that doesn't result in the desired effect as the updated string gets it's characters replaced as the script works through it so the 'img' in the first updated string gets replaced with with images and it all ends up quite a mess.  Is there a simpler way to do this?

$content = "abc" ;
$content = str_replace("a", "<img src=images/a.jpg >", $content);
$content = str_replace("b", "<img src=images/b.jpg >", $content);
$content = str_replace("c", "<img src=images/c.jpg >", $content);
$content = str_replace("d", "<img src=images/d.jpg >", $content);
$content = str_replace("e", "<img src=images/e.jpg >", $content);
$content = str_replace("f", "<img src=images/f.jpg >", $content);
$content = str_replace("g", "<img src=images/g.jpg >", $content);
$content = str_replace("h", "<img src=images/h.jpg >", $content);
$content = str_replace("i", "<img src=images/i.jpg >", $content);
$content = str_replace("j", "<img src=images/j.jpg >", $content);
$content = str_replace("k", "<img src=images/k.jpg >", $content);
$content = str_replace("l", "<img src=images/l.jpg >", $content);
$content = str_replace("m", "<img src=images/m.jpg >", $content);
$content = str_replace("n", "<img src=images/n.jpg >", $content);
$content = str_replace("o", "<img src=images/o.jpg >", $content);
$content = str_replace("p", "<img src=images/p.jpg >", $content);
$content = str_replace("q", "<img src=images/q.jpg >", $content);
$content = str_replace("r", "<img src=images/r.jpg >", $content);
$content = str_replace("s", "<img src=images/s.jpg >", $content);
$content = str_replace("t", "<img src=images/t.jpg >", $content);
$content = str_replace("u", "<img src=images/u.jpg >", $content);
$content = str_replace("v", "<img src=images/v.jpg >", $content);
$content = str_replace("w", "<img src=images/w.jpg >", $content);
$content = str_replace("x", "<img src=images/x.jpg >", $content);
$content = str_replace("y", "<img src=images/y.jpg >", $content);
$content = str_replace("z", "<img src=images/z.jpg >", $content);


echo $content ;

Any help would be gratefully appreciated.

Thanks
Megalos (paul)

Hey guys.  So I'm trying to write a script that replaces footnote citations in one format with footnote citations in another format.

For example, the text will read:   "Then he went down the street.[1] That is where the police found him [2].  They immediately arrested him at the house. [3]"

And I would like the script to find the [ #] strings and replace them with {#} ... so that the string reads:
"Then he went down the street.{1} That is where the police found him {2}.  They immediately arrested him at the house. {3}"

Note that there will be double, and even tripple, digit footnotes, so the script has to be able to recognize [##] or [###] and replace the brackets with {} accordingly.

I'm not really sure how to do this, since the "pattern" is constantly changing depending on the number between the brackets.  Ideas?

Thanks!

Please help.  I am trying to replace parenthesises () in a string with <>.  I tried preg_replace and str_replace, but was not success.

Here is what I have for str_replace:
$word = "(test)";

$word = str_replace('(', '<', $word);

$word = str_replace(array('(', ')'), array('<','>'), $word);