ifelse
The function nchar tells you how many characters long a character vector is. For example:
char_len <- nchar(murders$state)
head(char_len)
The function ifelse is useful because you convert a vector of logicals into something else. For example, some datasets use the number -999 to denote NA. A bad practice! You can convert the -999 in a vector to NA using the following ifelse call:
x <- c(2, 3, -999, 1, 4, 5, -999, 3, 2, 9)
ifelse(x == -999, NA, x)
If the entry is -999 it returns NA, otherwise it returns the entry.
This exercise is part of the course
Data Science R Basics
Exercise instructions
We will combine a number of functions for this exercise.
- Use the
ifelsefunction to write one line of code that assigns to the objectnew_namesthe state abbreviation when the state name is longer than 8 characters and assigns the state name when the name is not longer than 8 characters.
For example, where the original vector has Massachusetts (13 characters), the new vector should have MA. But where the original vector has New York (8 characters), the new vector should have New York as well.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Assign the state abbreviation when the state name is longer than 8 characters