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how to combain matrix with vector

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nadav regev
nadav regev on 12 Dec 2017
Closed: MATLAB Answer Bot on 20 Aug 2021
if I have matrix a = [9 8 7; 6 5 4] and vector v = [1 2 3 4 5] I want to combaine matrix like this
[9 8 7 inf inf; ...
6 5 4 inf inf; ...
1 2 3 4 5]
thank you!!

Answers (3)

KL
KL on 12 Dec 2017
Edited: KL on 12 Dec 2017
Something like this?
a = [9 8 7; 6 5 4];
v = [1 2 3 4 5];
sz = size(a);
a = [a inf(sz(1),size(v,2)-sz(2));v]
  4 Comments
KL
KL on 12 Dec 2017
Edited: KL on 12 Dec 2017
I agree with Jan.
@Birdman: Usually when you see a homework, doit4me tag (tagged by volunteers), you could choose not to answer or you could give them some hints rather than explicit answers.
For example the one on the below link was clearly a copy-paste of homework question, a typical doit4me.
Steven Lord
Steven Lord on 12 Dec 2017
And if it sounds like it may be homework but you're not certain, you can gently nudge the poster into offering more information. I tend to use something like "If you show us what you've already tried we may be able to offer some suggestions for how to proceed." to do that nudging.

Andrei Bobrov
Andrei Bobrov on 12 Dec 2017
Edited: Andrei Bobrov on 12 Dec 2017
a = [9 8 7; 6 5 4];
v = [1 2 3 4 5];
z = {a;v};
[ii,jj] = cellfun(@size,z);
n = max(jj);
out = cell2mat(arrayfun(@(x,y,k)[z{x},inf(k,n - y)],(1:numel(z))',jj,ii,'un',0))
or
a = [9 8 7; 6 5 4];
v = [1 2 3 4 5];
z = {a;v};
m = numel(z);
[ii,jj] = cellfun(@size,z);
n = max(jj);
i2 = cumsum(ii);
i1 = i2 - ii + 1;
out = inf(sum(ii),n);
for ii = 1:m
out(i1(ii):i2(ii),1:jj(ii)) = z{ii};
end
  1 Comment
Birdman
Birdman on 12 Dec 2017
Please do not provide direct solutions before seeing any effort from the user.

Jan
Jan on 12 Dec 2017
Edited: Jan on 12 Dec 2017
a = [9 8 7; 6 5 4];
v = [1 2 3 4 5];
out = padcat(a(1, :), a(2, :), v);
out(isnan(out)) = Inf;
Or write a function by your own:
% UNTESTED !!!
function Out = CatPadding(Dim, varargin)
In = varargin;
S1 = cellfun('size', In, 1);
S2 = cellfun('size', In, 2);
c = 1;
if Dim == 1
Out = Inf(sum(S1), max(S2));
for k = 1:numel(In)
Out(c:c+S1(k)-1, 1:S2(k)) = In{k};
c = c + S1(k);
end
elseif Dim == 2
Out = Inf(max(S1), sum(S2));
for k = 1:numel(In)
Out(1:S1(k), c:c+S2(k)-1) = In{k};
c = c + S2(k);
end
else
error('Only Dim=1 and Dim=2 implemented yet.')
end
And:
a = [9 8 7; 6 5 4];
v = [1 2 3 4 5];
Out = CatPadding(1, a, v)

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