How to compare a data frame with another data frame? - r

Question

I've got a Data Frame (df) with 4 Columns and n rows
df <- structure(list(x = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L,
11L, 12L, 13L, 1L, 2L), y = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 2L, 2L), pch = c(9L, 10L, 11L, 7L, 12L, 9L,
7L, 5L, 8L, 1L, 8L, 2L, 5L, 8L, 5L), col = c(7L, 8L, 3L, 3L,
4L, 6L, 3L, 4L, 2L, 1L, 7L, 5L, 4L, 7L, 6L)), class = "data.frame", row.names = c("1",
"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
"14", "15"))
x y pch col
1 1 1 9 7
2 2 1 10 8
3 3 1 11 3
4 4 1 7 3
5 5 1 12 4
6 6 1 9 6
7 7 1 7 3
8 8 1 5 4
9 9 1 8 2
10 10 1 1 1
11 11 1 8 7
12 12 1 2 5
13 13 1 5 4
14 1 2 8 7
15 2 2 5 6
and I want to compare the X and Y with another Data Frame 1x1 (df2)
df2 <- structure(list(V1 = 7, V2 = 1), class = "data.frame", row.names = c(NA,
-1L))
V1 V2
1 7 1
and if it is the same I want to take the entry( in this case number 7) to draw it into my grid with the pch and col which are written in the first Data Frame.
My attempt was compare it with a if loop but I don't know how to get the right column from the first Data frame. In this case x = 7 y = 1 pch = 7 and col = 3
if(input$V1 == playfield$x && input$V2 == playfield$y)
{
}
Appreciate every help or idea.

Answer 1

You can just do:
new_df <- playfield[playfield$x == input$V1 & playfield$y == input$V2,]

Answer 2

You could use right_join from dplyr
library(dplyr)
right_join(df, df2, by=c("x"="V1", "y"="V2"))
output:
x y pch col
1 7 1 7 3
data:
df <- structure(list(x = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L,
11L, 12L, 13L, 1L, 2L), y = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 2L, 2L), pch = c(9L, 10L, 11L, 7L, 12L, 9L,
7L, 5L, 8L, 1L, 8L, 2L, 5L, 8L, 5L), col = c(7L, 8L, 3L, 3L,
4L, 6L, 3L, 4L, 2L, 1L, 7L, 5L, 4L, 7L, 6L)), class = "data.frame", row.names = c("1",
"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
"14", "15"))
df2 <- structure(list(V1 = 7, V2 = 1), class = "data.frame", row.names = c(NA,
-1L))