library(stringr) #str_replace sal <- read.csv("salaries.csv") sal1 <- read.csv("salaries1.csv", header = F) colnames(sal1) <- c("Specialty", "Salary2018", "Salary2017") # substr (for substring) # > substr("$123", 2, 4) # [1] "123" # > substr("abcdefghij", 5, 8) # [1] "efgh" # > substr("abcdefghij", 5, 8000) # [1] "efghij" # > without.dollar <- substr(sal$X2017.2018.Average.Salary.Offer, 2, 50) without.comma <- str_replace(without.dollar, ",", "") salaries.numeric <- as.numeric(without.comma) salaries.numeric.net <- .55 * salaries.numeric str_replace("123,456", ",", "") str_replace("Harvard is number one", "Harvard", "Princeton") View(sal[1:10, 1:2]) sal[, "net.salary"] <- salaries.numeric.net