Search code examples
rstringuppercase

Making every other vowel in a vector uppercase

Given a lower case string. Ex:

s <- 'abcdefghijklmnopqrstuvwxyz'

The goal is to make every other vowel in the string an uppercase.

Desired output here:

abcdEfghijklmnOpqrstuvwxyz

As you can see, since all vowels where used in order, e and o where uppercase.

There are only lowercase characters in the strings in all cases.

For aieou, the desired output is:

aIeOu

How could I do this in R?

I tried:

s[unlist(strsplit(s, '')) %in% c('a', 'e', 'i', 'o', 'u')] <- toupper(s[unlist(strsplit(s, '')) %in% c('a', 'e', 'i', 'o', 'u')])

But no avail.

Even if this worked, it wouldn't be every other vowel

R version 4.1.1.

Solution

  • It's not a one-liner, but:

    s <- 'abcdefghijklmnopqrstuvwxyz'

as_list <- unlist(strsplit(s, ''))
vowels <- as_list %in% c('a', 'e', 'i', 'o', 'u')
every_other_index <- which(vowels)[c(FALSE, TRUE)]

as_list[every_other_index] <- toupper(as_list[every_other_index])

print(paste(as_list, collapse=''))

    gives:

    [1] "abcdEfghijklmnOpqrstuvwxyz"

    (Use of which taken from this question; use of c(FALSE, TRUE)] from here.)