Mutate

The function dplyr::mutate() allows you to:

Create new columns based on existing columns.
Modify existing columns
Delete columns

Dataset

For demonstration we’ll load the mammal_sleep_tbl data from the mgrtibbles package (hyperlink includes install instructions).

#Load package
library("mgrtibbles")
#mammal_sleep_tbl tibble for demonstration
mgrtibbles::mammal_sleep_tbl

# A tibble: 62 × 11
   species          body_wt brain_wt non_dreaming dreaming total_sleep life_span
   <chr>              <dbl>    <dbl>        <dbl>    <dbl>       <dbl>     <dbl>
 1 Africanelephant  6.65e+3   5.71           NA       NA           3.3      38.6
 2 Africangiantpou… 1   e+0   0.0066          6.3      2           8.3       4.5
 3 ArcticFox        3.38e+0   0.0445         NA       NA          12.5      14  
 4 Arcticgroundsqu… 9.2 e-1   0.0057         NA       NA          16.5      NA  
 5 Asianelephant    2.55e+3   4.60            2.1      1.8         3.9      69  
 6 Baboon           1.06e+1   0.180           9.1      0.7         9.8      27  
 7 Bigbrownbat      2.3 e-2   0.0003         15.8      3.9        19.7      19  
 8 Braziliantapir   1.6 e+2   0.169           5.2      1           6.2      30.4
 9 Cat              3.3 e+0   0.0256         10.9      3.6        14.5      28  
10 Chimpanzee       5.22e+1   0.44            8.3      1.4         9.7      50  
# ℹ 52 more rows
# ℹ 4 more variables: gestation <dbl>, predation <fct>, exposure <fct>,
#   danger <fct>

Create new column

Create a column of brain and body weight ratio.

mammal_sleep_tbl |>
    #Select columns of interest
    dplyr::select(species, body_wt, brain_wt) |>
    #Calculate and add brain_body_wt_ratio column
    dplyr::mutate(brain_body_wt_ratio = brain_wt/(body_wt*1000))

# A tibble: 62 × 4
   species                 body_wt brain_wt brain_body_wt_ratio
   <chr>                     <dbl>    <dbl>               <dbl>
 1 Africanelephant        6654       5.71           0.000000858
 2 Africangiantpouchedrat    1       0.0066         0.0000066  
 3 ArcticFox                 3.38    0.0445         0.0000131  
 4 Arcticgroundsquirrel      0.92    0.0057         0.00000620 
 5 Asianelephant          2547       4.60           0.00000181 
 6 Baboon                   10.6     0.180          0.0000170  
 7 Bigbrownbat               0.023   0.0003         0.0000130  
 8 Braziliantapir          160       0.169          0.00000106 
 9 Cat                       3.3     0.0256         0.00000776 
10 Chimpanzee               52.2     0.44           0.00000844 
# ℹ 52 more rows

Create a column for life time sleep

mammal_sleep_tbl |>
    #Select columns of interest
    dplyr::select(species, total_sleep, life_span) |>
    #Calculate and add total_life_sleep column
    dplyr::mutate(total_life_sleep = (life_span*365.25) * total_sleep)

# A tibble: 62 × 4
   species                total_sleep life_span total_life_sleep
   <chr>                        <dbl>     <dbl>            <dbl>
 1 Africanelephant                3.3      38.6           46526.
 2 Africangiantpouchedrat         8.3       4.5           13642.
 3 ArcticFox                     12.5      14             63919.
 4 Arcticgroundsquirrel          16.5      NA                NA 
 5 Asianelephant                  3.9      69             98289.
 6 Baboon                         9.8      27             96645.
 7 Bigbrownbat                   19.7      19            136713.
 8 Braziliantapir                 6.2      30.4           68842.
 9 Cat                           14.5      28            148292.
10 Chimpanzee                     9.7      50            177146.
# ℹ 52 more rows

NA filling

For NA filling/editing please see the tidyr drop NA page.