can u elaborate where is the input and where to print

What about 'Y' ? :)

The "comments" are given as the parameter str. When a function is called you have the option of including parameters, which are local variables only visible to the function.

str is a variable and you must look at this instead, not the self created variable "comment". Your variable "comment" is static and will not change, but str is dynamic. Change your variable name of your regex to something else, so as it does not replace the original parameter.

As kazk says, the problem is using "...array" when given null. You should check for null before using "...array".

I think that error comes from ...array when given null.

Next time, mark your comment as spoiler.