substring of last N characters in R

Question

How to store substring of last N characters from a data frame field in R?

Answer 1

Use below code - 

If the elements within the field have fixed length then directly give the position values like below - 

substring(table$field_name,4,8)

If the length of elements in the field is varying then use nchar() to find the length of string like below -

substring(table$field_name,nchar(table$field_name)-4,nchar(table$field_name))