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Exercise

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.

Instructions

100 XP

We will combine a number of functions for this exercise.

  • Use the ifelse function to write one line of code that assigns to the object new_names the 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.