Change values in a column of an R data frame

change-values-column.R

library(tidyverse)

#### Changing the values in a character/numeric vector ####

# Create sample data frame
df <- data.frame(
  col1 = c("A", "A", "A", "A", "B", "B", "B", "B"), 
  col2 = c("C", "C", "D", "D", "C", "C", "D", "D"),
  col3 = c("E", "F", "E", "F", "E", "F", "E", "F"), 
  stringsAsFactors = FALSE
)

# Change values in col1 from "A" to "Apple"
# From https://stackoverflow.com/questions/35610437/using-dplyr-to-conditionally-replace-values-in-a-column
df <- df %>%
  mutate(col1 = replace(col1, col1 == "A", "Apple"))
  
#### Changing the value of a factor ####

# Create sample data frame
df <- data.frame(
  col1 = c("A", "A", "A", "A", "B", "B", "B", "B"), 
  col2 = c("C", "C", "D", "D", "C", "C", "D", "D"),
  col3 = c("E", "F", "E", "F", "E", "F", "E", "F"), 
  stringsAsFactors = TRUE
)

# Change values in col1 from "A" to "Apple". Change is made directly to df, don't need to reassign.
# From http://www.cookbook-r.com/Manipulating_data/Renaming_levels_of_a_factor/
levels(df)[levels(df) == "A"] <- "Apple"