为什么PHP在ltrim或str_replace之后改变了第一个字符？

Question

I'm trying to remove a part of a directory with PHPs ltrim(), however the result is unexpected. The first letter of my result has the wrong ascii value, and shows up as missing character/box in the browser.

Here is my code:

$stripPath = "public\docroot\4300-4399\computer-system-upgrade";
$directory = "public\docroot\4300-4399\computer-system-upgrade\3.0 Outgoing Documents";

$shortpath = ltrim($directory, $stripPath);
echo $shortpath;

Expected output:

3.0 Outgoing Documents

Actual output:

.0 Outgoing Documents

Note the invisible/non-print character before the dot. Ascii value changed from Hex 33 (the number 3) to Hex 03 (invisible character). I also tried str_replace() instead of trim(), but the result stays the same.

What am i doing wrong here? How would i get the expected result "3.0 Outgoing Documents"?

Answer 1

Don't use ltrim.
Ltrim does not replace straight off. It strips kind of like regex does.
Meaning all characters you put in the second argument is used to remove anything.
See example: https://3v4l.org/AfsHJ
The reason it stops at . is because it's not part of $stripPath

You should instead do is use real regex or simple str_replace.

$stripPath = "public\docroot\4300-4399\computer-system-upgrade";
$directory = "public\docroot\4300-4399\computer-system-upgrade\3.0 Outgoing Documents";

 $shortpath = str_replace($stripPath, "", $directory);
 echo $shortpath;

https://3v4l.org/KF2Iv