Hi,
You can use squared brackets to select rows and columns of a data frame, here are some examples:
# sample data'
mydf<-head(mtcars)
mydf
#> 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
#> Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
# Use numeric indices subset columns
mydf[,c(1,3,6)]
#> mpg disp wt
#> Mazda RX4 21.0 160 2.620
#> Mazda RX4 Wag 21.0 160 2.875
#> Datsun 710 22.8 108 2.320
#> Hornet 4 Drive 21.4 258 3.215
#> Hornet Sportabout 18.7 360 3.440
#> Valiant 18.1 225 3.460
# Use the column names to select columnns
mydf[,c("mpg","disp","wt")]
#> mpg disp wt
#> Mazda RX4 21.0 160 2.620
#> Mazda RX4 Wag 21.0 160 2.875
#> Datsun 710 22.8 108 2.320
#> Hornet 4 Drive 21.4 258 3.215
#> Hornet Sportabout 18.7 360 3.440
#> Valiant 18.1 225 3.460
# Use a logical vector to subset a column
mydf[,c(T,F,T,F,F,T,F,F,F,F,F)]
#> mpg disp wt
#> Mazda RX4 21.0 160 2.620
#> Mazda RX4 Wag 21.0 160 2.875
#> Datsun 710 22.8 108 2.320
#> Hornet 4 Drive 21.4 258 3.215
#> Hornet Sportabout 18.7 360 3.440
#> Valiant 18.1 225 3.460
Created on 2021-01-02 by the reprex package (v0.3.0)
To select rows, you do the same before the comma.
Another very popular option to select columns is dplyr::select():
suppressPackageStartupMessages(
library(dplyr)
)
# sample data'
mydf<-head(mtcars)
mydf
#> 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
#> Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
# select columns
mydf%>%select(mpg,disp,drat)
#> mpg disp drat
#> Mazda RX4 21.0 160 3.90
#> Mazda RX4 Wag 21.0 160 3.90
#> Datsun 710 22.8 108 3.85
#> Hornet 4 Drive 21.4 258 3.08
#> Hornet Sportabout 18.7 360 3.15
#> Valiant 18.1 225 2.76
Created on 2021-01-02 by the reprex package (v0.3.0)
Does this answer your question?