A.6 Add/Edit columns with mutate

Let’s add a column to our data frame for home score differential (home score minus away score). We can add columns to our data frame, or edit existing columns, in base R like this.

Code
d$diff = d$hscore - d$ascore
head(d)
        date      gid away home ascore hscore diff
1 2021-10-19 22100001  BKN  MIL    104    127   23
2 2021-10-19 22100002  GSW  LAL    121    114   -7
3 2021-10-20 22100011  OKC  UTA     86    107   21
4 2021-10-20 22100013  SAC  POR    124    121   -3
5 2021-10-20 22100012  DEN  PHX    110     98  -12
6 2021-10-20 22100010  ORL  SAS     97    123   26

This can also be done by using mutate.

Code
d = d %>% 
  mutate(diff = hscore - ascore)
head(d)
        date      gid away home ascore hscore diff
1 2021-10-19 22100001  BKN  MIL    104    127   23
2 2021-10-19 22100002  GSW  LAL    121    114   -7
3 2021-10-20 22100011  OKC  UTA     86    107   21
4 2021-10-20 22100013  SAC  POR    124    121   -3
5 2021-10-20 22100012  DEN  PHX    110     98  -12
6 2021-10-20 22100010  ORL  SAS     97    123   26