从字符串中删除倒数第二个字符（连字符）

I have a string like:

01-17-11-4

and want to get like:

01-17-114

How to do that in php?

I have tried following:

  substr_replace(implode('-', str_split($student->account_no, 2)), "", -1) 

but it remove the last character like:

01-17-11-

Using substr() which allows you to take parts of a string this first chops off the last 2 characters (using -2 as the length) and then adds the last character back on...

echo substr($student->account_no, 0, -2).substr($student->account_no, -1);