How to substring ( text and emoji ) ?

[edmonleung300]

Hello, How can I substring text and emoji ?
I have the input, and my output will be max length 100 characters. My input has both text and random emoji.

I tried use Substring from "Text Processing", but sometime it work, sometime it not

 

[VladZen]

please explain what's with taking substring... not clear.

 

[edmonleung300]

please explain what's with taking substring... not clear.

I got it, some emoji they do not work.
For example , if my input has this (emoji), I can not substring my input

 

[VladZen]

I got it, some emoji they do not work.
For example , if my input has this (emoji), I can not substring my input

Looks like some unreadable characters.