Using pivotlonger on multiple variables of horse racing dataframe in R - r

Question

Hi and Thanks in advance for any assistance the group can give.
I have a dataset which gives the performance ratings for 7 race horses
over their last 3 races. The performance ratings are DaH1, DaH2 and DaH3 where
DaH1 is the performance rating for the last race etc.
I also have data for race distances over which the races were ran, where the distances are
Dist1, Dist2 and Dist3 and they correspond to the performance ratings. ie. Horse 2 has a
performance rating of 124 for DaH1, with a race distance, Dist1, of 12.
The dataset is:
horse_data <- tibble(
DaH1=c(0, 124, 121, 123, 0, NA, 110),
DaH2=c(124, 117, 125, 120, 125, 0, NA),
DaH3=c(121, 119, 123, 119, NA, 0, 123),
Dist1 =c(10,12,10.3,11,11.5,14,10),
Dist2 =c(10,10.1,12,8,9.5,10.25,8.75),
Dist3 =c(11.5,12.5,9.8,10,10,15,10),
horse =c(1,2,3,4,5,6,7),
)
I am trying to use pivot_longer to convert the data to a better dataset for performing
calculations depending upon race distances.
So far I used this code:
tidyData <- horse_data %>%
pivot_longer(
values_to="Rating",
cols=c(DaH1, DaH2, DaH3),
names_prefix="DaH",
names_to="RaceIdx"
)
To achieve:
> tidyData
# A tibble: 21 x 6
Dist1 Dist2 Dist3 horse RaceIdx Rating
<dbl> <dbl> <dbl> <dbl> <chr> <dbl>
1 10 10 11.5 1 1 0
2 10 10 11.5 1 2 124
3 10 10 11.5 1 3 121
4 12 10.1 12.5 2 1 124
5 12 10.1 12.5 2 2 117
6 12 10.1 12.5 2 3 119
7 10.3 12 9.8 3 1 121
8 10.3 12 9.8 3 2 125
9 10.3 12 9.8 3 3 123
10 11 8 10 4 1 123
# ... with 11 more rows
Where RaceIdx is the race number.
This has achieved the desired result for 'Rating' column but I need to be able to convert
Dist1, Dist2 and Dist3 in to a separate column 'Distance' that matches up each horses
corresponding DaH rating with Dist.
To illustrate, I am trying to end up with a dataset as follows:
Distance horse RaceIdx Rating
<dbl> <dbl> <chr> <dbl>
1 10 1 1 0
2 10 1 2 124
3 11 1 3 121
4 12 2 1 124
5 10.1 2 2 117
6 12.5 2 3 119
7 10.3 3 1 121
8 12 3 2 125
9 9.8 3 3 123
10 11 4 1 123
# ... with 11 more rows
I need to filter the Ratings by Distance.
Then I hope to be able to produce average ratings for each horse ratings where the
race Distance is between 10 and 11.
Many Thanks in advance.

Answer 1

We can specify the names_sep with a regex lookaround
library(dplyr)
library(tidyr)
horse_data %>%
pivot_longer(cols = -c(horse), names_to = c('.value', 'RaceIdx'),
names_sep="(?<=[A-Za-z])(?=[0-9])") %>%
rename(Distance = Dist, Rating = DaH)
# A tibble: 21 x 4
# horse RaceIdx Rating Distance
# <dbl> <chr> <dbl> <dbl>
# 1 1 1 0 10
# 2 1 2 124 10
# 3 1 3 121 11.5
# 4 2 1 124 12
# 5 2 2 117 10.1
# 6 2 3 119 12.5
# 7 3 1 121 10.3
# 8 3 2 125 12
# 9 3 3 123 9.8
#10 4 1 123 11
# … with 11 more rows