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Re: Combine matrices of equal height

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  • Subject: [mg111034] Re: Combine matrices of equal height
  • From: "David Park" <djmpark at>
  • Date: Sun, 18 Jul 2010 01:02:15 -0400 (EDT)

Here are two sample matrices.

m1 = Array[1 &, {3, 2}];
m2 = Array[2 &, {3, 3}]; 

Transpose[Join[Transpose[m1], Transpose[m2]]] // MatrixForm 

Another method that doesn't explicitly use Join and Transpose is to make a
new  blank matrix first and then fill in the parts using the Span notation.
This might be more intuitive.

m3 = Array[0 &, {3, 5}];
m3[[All, 1 ;; 2]] = m1;
m3[[All, 3 ;; 5]] = m2;
m3 // MatrixForm 

David Park
djmpark at  

From: Sam Takoy [mailto:sam.takoy at] 


Given two matrices of equal height, what's the best way to combine them. 
Here's what I did

TF[m_] := Flatten[Transpose[m]]
Combine[m1_, m2_] :=
  Partition[Join[m1 // TF, m2 // TF], Length[m1]] // T

Surely there's a better way of doing it.


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