multiple a vector by a scalar using dot error

Question

Robert Scott 2021-7-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/888832-multiple-a-vector-by-a-scalar-using-dot-error

回答： DGM 2021-7-29

So yet another problem for my day

I am trying to multiply a simple cell array fill of ints by a scalar value

if i print out

my_array{1:end , 1}

I get a bunch of ints back

However if i say

my_array{1:end , 1} * 5

I get a "too many input arguments" error from matlab

One would assume you need element wise multiplication here

So i resort to

my_array{1:end , 1} .* 5

And guess what, same error

too many input arguments

How is that even possible?

Suggestions?

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Answer 1

DGM 2021-7-29

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/888832-multiple-a-vector-by-a-scalar-using-dot-error#answer_756892

在 MATLAB Online 中打开

I guess I already mentioned this, but

A = num2cell(reshape(1:70,10,[]))
A = 10×7 cell array
    {[ 1]}    {[11]}    {[21]}    {[31]}    {[41]}    {[51]}    {[61]}
    {[ 2]}    {[12]}    {[22]}    {[32]}    {[42]}    {[52]}    {[62]}
    {[ 3]}    {[13]}    {[23]}    {[33]}    {[43]}    {[53]}    {[63]}
    {[ 4]}    {[14]}    {[24]}    {[34]}    {[44]}    {[54]}    {[64]}
    {[ 5]}    {[15]}    {[25]}    {[35]}    {[45]}    {[55]}    {[65]}
    {[ 6]}    {[16]}    {[26]}    {[36]}    {[46]}    {[56]}    {[66]}
    {[ 7]}    {[17]}    {[27]}    {[37]}    {[47]}    {[57]}    {[67]}
    {[ 8]}    {[18]}    {[28]}    {[38]}    {[48]}    {[58]}    {[68]}
    {[ 9]}    {[19]}    {[29]}    {[39]}    {[49]}    {[59]}    {[69]}
    {[10]}    {[20]}    {[30]}    {[40]}    {[50]}    {[60]}    {[70]}
A{2:2:end,7} % this expression has multiple outputs (multiple scalars)
ans = 62
ans = 64
ans = 66
ans = 68
ans = 70
vertcat(A{2:2:end,7}) % this expression has only one output (a vector)
ans = 5×1
    62
    64
    66
    68
    70
vertcat(A{2:2:end,7}) * 2 % this works
ans = 5×1
   124
   128
   132
   136
   140
A{2:2:end,7} * 2 % this doesn't
Error using *
Too many input arguments.