Flip an array.

Flip an array along some dimension(s), e.g. flip a matrix upside down or left to right.

flip(x, dim = 1)

Arguments

x	an array
dim	dimension(s) along which to flip (in sequence), defaults to 1 (i.e. flip rows).

Value

The array x having the dim dimension flipped.

Examples

# flip a matrix
x<-matrix(1:6,2)
x
#>      [,1] [,2] [,3]
#> [1,]    1    3    5
#> [2,]    2    4    6
# flip upside down
flip(x,1)
#>      [,1] [,2] [,3]
#> [1,]    2    4    6
#> [2,]    1    3    5
# flip left to right
flip(x,2)
#>      [,1] [,2] [,3]
#> [1,]    5    3    1
#> [2,]    6    4    2
# flip both upside down and left to right
flip(x,1:2)
#>      [,1] [,2] [,3]
#> [1,]    6    4    2
#> [2,]    5    3    1

# flip a vector
v<-1:10
v
#>  [1]  1  2  3  4  5  6  7  8  9 10
flip(v)
#>  [1] 10  9  8  7  6  5  4  3  2  1

# flip an array
a<-array(1:prod(2:4),2:4)
a
#> , , 1
#> 
#>      [,1] [,2] [,3]
#> [1,]    1    3    5
#> [2,]    2    4    6
#> 
#> , , 2
#> 
#>      [,1] [,2] [,3]
#> [1,]    7    9   11
#> [2,]    8   10   12
#> 
#> , , 3
#> 
#>      [,1] [,2] [,3]
#> [1,]   13   15   17
#> [2,]   14   16   18
#> 
#> , , 4
#> 
#>      [,1] [,2] [,3]
#> [1,]   19   21   23
#> [2,]   20   22   24
#> 
# flip along dim 1
flip(a,1)
#> , , 1
#> 
#>      [,1] [,2] [,3]
#> [1,]    2    4    6
#> [2,]    1    3    5
#> 
#> , , 2
#> 
#>      [,1] [,2] [,3]
#> [1,]    8   10   12
#> [2,]    7    9   11
#> 
#> , , 3
#> 
#>      [,1] [,2] [,3]
#> [1,]   14   16   18
#> [2,]   13   15   17
#> 
#> , , 4
#> 
#>      [,1] [,2] [,3]
#> [1,]   20   22   24
#> [2,]   19   21   23
#> 
# flip along dim 2
flip(a,2)
#> , , 1
#> 
#>      [,1] [,2] [,3]
#> [1,]    5    3    1
#> [2,]    6    4    2
#> 
#> , , 2
#> 
#>      [,1] [,2] [,3]
#> [1,]   11    9    7
#> [2,]   12   10    8
#> 
#> , , 3
#> 
#>      [,1] [,2] [,3]
#> [1,]   17   15   13
#> [2,]   18   16   14
#> 
#> , , 4
#> 
#>      [,1] [,2] [,3]
#> [1,]   23   21   19
#> [2,]   24   22   20
#> 
# flip along dim 3
flip(a,3)
#> , , 1
#> 
#>      [,1] [,2] [,3]
#> [1,]   19   21   23
#> [2,]   20   22   24
#> 
#> , , 2
#> 
#>      [,1] [,2] [,3]
#> [1,]   13   15   17
#> [2,]   14   16   18
#> 
#> , , 3
#> 
#>      [,1] [,2] [,3]
#> [1,]    7    9   11
#> [2,]    8   10   12
#> 
#> , , 4
#> 
#>      [,1] [,2] [,3]
#> [1,]    1    3    5
#> [2,]    2    4    6
#>