# sortrows

sortrows(A, [alg=,] [by=,] [lt=,] [rev=false])

Sort the rows of matrix A lexicographically.

## Examples

1. Sort rows lexicographically:

julia> A = [3 2 1; 6 5 4; 9 8 7];
julia> sortrows(A)
3×3 Array{Int64,2}:
3  2  1
6  5  4
9  8  7

This example sorts the rows of matrix A in lexicographic order.

2. Sort rows based on specific columns:

julia> B = [3 2 1; 6 5 4; 9 8 7];
julia> sortrows(B, by = x -> x[2])
3×3 Array{Int64,2}:
3  2  1
9  8  7
6  5  4

By using the by argument, you can specify a transformation x -> x[2] to sort the rows based on the second column.

3. Sort rows in reverse order:

julia> C = [9 8 7; 6 5 4; 3 2 1];
julia> sortrows(C, rev = true)
3×3 Array{Int64,2}:
9  8  7
6  5  4
3  2  1

Setting rev = true sorts the rows in reverse order.

4. Specify sorting algorithm:
julia> D = [9 8 7; 6 5 4; 3 2 1];
julia> sortrows(D, alg = QuickSort)
3×3 Array{Int64,2}:
3  2  1
6  5  4
9  8  7

The alg argument allows you to specify the sorting algorithm. In this example, QuickSort is used.

Common mistake example:

julia> E = [3 2 1; 6 5 4; 9 8 7];
julia> sortrows(E, by = x -> x[4])
ERROR: BoundsError: attempt to access 3×3 Array{Int64,2} at index [CartesianIndex(1, 4)]

In this example, the by argument is attempting to access the fourth element of each row, but the matrix E only has three columns. It's important to ensure that the specified column index is within the valid range of the matrix before using sortrows.