unicode Characters can consist of multiple code points
Remarks
An Unicode code point, what programmers often think of one character, often corresponds to what the user thinks is one character. Sometimes however a “character” is made up of multiple code points, as the examples above show.
This means that operations like slicing a string, or getting a character at a given index may not work as expected. For instance the 4th character of the string "Café" is 'e' (without the accent). Similarly, clipping the string to length 4 will remove the accent.
The technical term for such a group of code points is a grapheme cluster. See UAX #29: Unicode Text Segmentation
