I'm still learning some very basic concepts in R. I have an excel file that I import into R, but it has atrocious variable names. I have another file with 2 columns: the first is the original column names in my data file, the second is what I want the variable names to be.
What's the most efficient way to update all column names using this auxiliary file that I have?
This method is a little overkill if all columns are perfectly accounted for and in the correct order. If there are columns out of order or new columns, however, this method is robust by only changing those you intend to change and are found.
mt <- mtcars
head(mt, 3)
# mpg cyl disp hp drat wt qsec vs am gear carb
# Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
# Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
# Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
namechange <- data.frame(oldname = c("mpg", "cyl", "hp"), newname = c("MPG", "CYL", "HP"))
namechange
# oldname newname
# 1 mpg MPG
# 2 cyl CYL
# 3 hp HP
ind <- match(names(mtcars), namechange$oldname)
ind
# [1] 1 2 NA 3 NA NA NA NA NA NA NA
ifelse(is.na(ind), names(mt), namechange$newname[ind])
# [1] "MPG" "CYL" "disp" "HP" "drat" "wt" "qsec" "vs" "am" "gear" "carb"
names(mt) <- ifelse(is.na(ind), names(mt), namechange$newname[ind])
head(mt, 3)
# MPG CYL disp HP drat wt qsec vs am gear carb
# Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
# Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
# Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
Since names or colnames of data frames is a character vector and every column in a data frame is an atomic vector, simply re-assign original with new names.
str(names_df)
# EXPECTED TWO COLUMNS OF CHR TYPE
# RE-ORDER COLUMNS BY PASSING CHARACTER VECTOR
excel_df <- excel_df[names_df$original_names]
# RE-ASSIGN NAMES: TWO METHODS
names(excel_df) <- names_df$new_names
excel_df <- setNames(excel_df, names_df$new_names)
you can use the rename command
library(dplyr)
#Exemple with base mtcars
View(mtcars)
new_mtcars<-mtcars%>%
rename('new_MPG'='mpg', 'new_cyl'='cyl')#Change the columns mpg and cyl
View(new_mtcars)
output
