如何将字符串向量的最后一个字符大写？

Question

我刚刚开始使用R，我想知道如何创建一个将字符串向量的最后一个字符大写的函数。

Answer 1

基础R regex。

words <- c("hello", "world")

# Last character of last word in vec element: 
gsub("(\\w$)", "\\U\\1", words, perl = TRUE)

sentences <- c("hello world", "hello friend")

# Last character of sentence: 
gsub("(\\w$)", "\\U\\1", sentences, perl = TRUE)

# Last character of each word in the sentence: 
gsub("(\\w\\s+|\\w$)", "\\U\\1", sentences, perl = TRUE)