Creating a function to supply parameters to another function that exists - r

Question

Right now, I have a main function (let's call it performance()) that has as its arguments player1, player2, and team_of_interest.
I have a data set that looks like this:
> head(roster_van, 3)
team_name team venue num_first_last
1 VANCOUVER CANUCKS VAN Home 5 SBISA, LUCA
2 VANCOUVER CANUCKS VAN Home 8 TANEV, CHRISTOPHER
3 VANCOUVER CANUCKS VAN Home 14 BURROWS, ALEXANDRE
game_date game_id season session player_number
1 2016-10-15 2016020029 20162017 R 5
2 2016-10-15 2016020029 20162017 R 8
3 2016-10-15 2016020029 20162017 R 14
team_num first_name last_name player_name
1 VAN5 LUCA SBISA LUCA.SBISA
2 VAN8 CHRISTOPHER TANEV CHRIS.TANEV
3 VAN14 ALEXANDRE BURROWS ALEX.BURROWS
name_match player_position
1 LUCASBISA D
2 CHRISTOPHERTANEV D
3 ALEXANDREBURROWS L
This is the roster data for a hockey games played in a season.
I want to create another function (let's call it players()) that loops through every unique pair of players in a hockey team and provides their names and team to the player1, player2, and team_of_interest arguments inside the performance() function.
I've started off with this, but don't know what next to do:
name_pairs <- function(x,y) {
x <- seq(1,19, by = 2)
y <- x+1
}

Answer 1

merge can make quick work of generating a cartesian join out of your dataframe.
With a shortened version of your sample dataframe and a guess at the team_of_interest column.
library(tidyverse)
roster_van <- tibble(team = "VAN",
team_num = c(5, 8, 14),
player_name = c("LUCA.SBISA", "CHRIS.TANEV", "ALEX.BURROWS"),
player_position = c("D", "D", "L"),
team_of_interest = c("SL BLUES", "BOS BRUINS", "CGY FLAMES")
)
roster_van
> roster_van
# A tibble: 3 x 5
team team_num player_name player_position team_of_interest
<chr> <dbl> <chr> <chr> <chr>
1 VAN 5 LUCA.SBISA D SL BLUES
2 VAN 8 CHRIS.TANEV D BOS BRUINS
3 VAN 14 ALEX.BURROWS L CGY FLAMES
If you only want a few of the columns repeated, then only rename the column names you wish to see joined again onto the original dataframe before you filter off the equal self joins.
roster_van_pairs <-
roster_van %>%
merge(roster_van %>%
select(team,
team_num_paired = team_num,
player_name_paired = player_name
)
) %>%
filter(player_name != player_name_paired)
roster_van_pairs
> roster_van_pairs
team team_num player_name player_position team_of_interest team_num_paired player_name_paired
1 VAN 5 LUCA.SBISA D SL BLUES 8 CHRIS.TANEV
2 VAN 5 LUCA.SBISA D SL BLUES 14 ALEX.BURROWS
3 VAN 8 CHRIS.TANEV D BOS BRUINS 5 LUCA.SBISA
4 VAN 8 CHRIS.TANEV D BOS BRUINS 14 ALEX.BURROWS
5 VAN 14 ALEX.BURROWS L CGY FLAMES 5 LUCA.SBISA
6 VAN 14 ALEX.BURROWS L CGY FLAMES 8 CHRIS.TANEV
If you want to go with a bulk approach which will join all the columns in again, you can execute a full rename of all the columns with the code below:
roster_van_copy <- roster_van
# provenience the data quickly
colnames(roster_van_copy) <- colnames(roster_van_copy) %>% paste0(., "_paired")
This makes the cross join code more concise, too:
roster_van_all_columns_paired <-
roster_van %>%
merge(roster_van_copy) %>%
filter(player_name != player_name_paired)
I imagine this will leave you with more columns than necessary, but they are very easy to remove with a select(-c(<col_x:col_y)) after all.
roster_van_all_columns_paired
> roster_van_all_columns_paired
team team_num player_name player_position team_of_interest team_paired team_num_paired player_name_paired
1 VAN 8 CHRIS.TANEV D BOS BRUINS VAN 5 LUCA.SBISA
2 VAN 14 ALEX.BURROWS L CGY FLAMES VAN 5 LUCA.SBISA
3 VAN 5 LUCA.SBISA D SL BLUES VAN 8 CHRIS.TANEV
4 VAN 14 ALEX.BURROWS L CGY FLAMES VAN 8 CHRIS.TANEV
5 VAN 5 LUCA.SBISA D SL BLUES VAN 14 ALEX.BURROWS
6 VAN 8 CHRIS.TANEV D BOS BRUINS VAN 14 ALEX.BURROWS
player_position_paired team_of_interest_paired
1 D SL BLUES
2 D SL BLUES
3 D BOS BRUINS
4 D BOS BRUINS
5 L CGY FLAMES
6 L CGY FLAMES
Base R approach could look like this:
roster.van.all.copy.baseR <- merge(roster_van, roster_van_copy)
roster.van.all.baseR <- roster.van.all.copy.baseR[ which(roster.van.all.copy.baseR$player_name != roster.van.all.copy.baseR$player_name_paired), ]