First look makeup match function
matchFunction has four parameters. match(x, table, nomatch = NA_integer_, incomparables = NULL)x: Indicates that the query objects table: indicates the matching value, may be in the form of a vector nomatch: If no match the value returned, the default is NA incomparables: setting an invalid value matching parameter table, the default setting is not (NULL)
By default, in order to match the tag does not match the return NA
x <- c("A","A","B","B","C","D")
match(x,c("A","C","B"))
#[1] 1 1 3 3 2 NA
Nomatch parameter setting, so as not to match returns 0
match(x,c("A","C","B"),0)
#[1] 1 1 3 3 2 0
Set incomparables parameters, ignoring C
match(x,c("A","C","B"),incomparables = "C")
#[1]1 1 3 3 NA NA
Note: Although set to ignore C, but it is still involved in ranking, so the results only 1,3, 2 no.
If two vector elements identical but in a different order, how to rearrange
x <- c("A","B","C","D","E")
y <- c("B","D","E","A","C")
match(x,y)
#[1] 4 1 5 2 3
y[match(x,y)]
#[1] "A" "B" "C" "D" "E"
Since it involves the sort to tell you rank, order, sort
fact, the earlier example can be directly sort(y)addressed.
rank(c(3,1,2,5,4))
#[1] 3 1 2 5 4
order(c(3,1,2,5,4))
#[1] 2 3 1 5 4
sort(c(3,1,2,5,4))
#[1] 1 2 3 4 5
rev(c(3,1,2,5,4))
#[1] 4 5 2 1 3
rank return value means: the original vector of the first element row 3, the second element of a first row, and so on.
order means the return value: the minimum value of 2, the next smallest value of the bit in the third. . . The maximum value at position 4
is relatively simple sort, I sent a small to large order.
rev is the vector elements output from back to front.
More intuitive look, with just an example of y
rank(y)
#[1] 2 4 5 1 3
order(y)
#[1] 4 1 5 2 3
sort(y)
#[1] "A" "B" "C" "D" "E"
rev(y)
#[1] "C" "A" "E" "D" "B"
Reproduced in: https: //www.jianshu.com/p/fba990bde546