### 2.5 Insert a column into a matrix

The problem is to insert a column into the second column position in a 2D matrix.

Mathematica

 mat = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}; mat = Insert[Transpose[mat], {90, 91, 92}, 2]; mat = Transpose[mat]   {{1,90,2,3}, {4,91,5,6}, {7,92,8,9}} 

Matlab

 A=[1 2 3; 4 5 6; 7 8 9]; A=[A(:,1) [90 91 92]' A(:,2:end) ]   1 90 2 3 4 91 5 6 7 92 8 9 

Fortran

 program t4 implicit none integer(4) ::i integer(4), ALLOCATABLE ::A(:,:) A = reshape ([1,2,3, & 4,5,6, & 7,8,9], [3,3], order=[2,1]) A = reshape ([A(:,1), [90,91,92] , A(:,2:)] , [3,4]) do i=LBOUND(A, 1),UBOUND(A, 1) print *,A(i,:) end do end program t4  >gfortran t4.f90 >./a.out 1 90 2 3 4 91 5 6 7 92 8 9 

Maple

 A:=< <1|2|3>,<4|5|6>,<7|8|9>>; A:=< A(..,1)|<90,91,92>|A(..,2..)>;  Using Matrix/Vector A:=Matrix([ [1,2,3],[4,5,6],[7,8,9]]); A:=Matrix([ [A[..,1], Vector[column]([91,92,92]), A[..,2..] ]]);  [ 1 90 2 3 4 91 5 6 7 92 8 9] 

Python

 import numpy as np mat=np.array([[1,2,3], [4,5,6], [7,8,9]]) mat=numpy.insert(mat,1,[90,91,92],1)  array([[ 1, 90, 2, 3], [ 4, 91, 5, 6], [ 7, 92, 8, 9]])