This function returns a character row vector that is a valid
The return value has the same length as the character row vector
v and is as close to v as possible.
If the first character of v is not a
letter, it is converted to an underbar in the return value.
If any other character of v is not a letter or a
number between "0" and "9", it is also converted to an underbar
in the return value.
If you enter
char2id("Size of Truck")
O-Matrix will respond