R language Data de-weight

R language commonly used to de-order a unique duplicated

Unique is to return a vector, a data frame, or an array that deletes a repeating element or row.

> x <-C (3:5, 11:8, 8 + 0:5)
> x
[1] 3 4 5 11 10 9 8 8 9 10 11 12 13
> Unique (x)
[1] 3 4 5 11 10 9 8 12 13
> Unique (x, fromlast = TRUE)
[1] 3 4 5 8 9 #排序后的

> A
[, 1] [, 2] [, 3]
[1,] 1 2 3
[2,] 1 2 4
[3,] 1 3 5
[4,] 1 2 3

> Unique (a)
[, 1] [, 2] [, 3]
[1,] 1 2 3
[2,] 1 2 4
[3,] 1 3 5 #去除重复的最后一行

Duplicated is the main determinant of whether or not the elements in a vector or data frame are duplicated, it returns an element (row) is not a repeating logical vector

> Duplicated (a)
[1] False False TRUE # Returns whether a duplicate logical judgment

> a[!duplicated (a),]
[, 1] [, 2] [, 3]
[1,] 1 2 3
[2,] 1 2 4
[3,] 1 3 5 #去除重复的最后一行

If the second column has a duplicate removal, you need to add an index

> Index <-duplicated (a[,2])
> Index
[1] False true False
> A[!index,]
[, 1] [, 2] [, 3]
[1,] 1 2 3
[2,] 1 3 5

R language Data de-weight