Indexed Assignment on the Right Side

2020 11 17
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更新时间：2020 11 18
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I am calling function f(x) that returns a matrix of 100 columns.
All what I need is just the 10th column. So I need one vector from the whole returned matrix.
I need to get rid of 99 columns and retain only the 10th column.
In Julia, this can be done by:
columnTen = f(x)[:,10]
I am dying to do the same thing in MATLAB.
Not sure why this simple operation seems impossible.

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Walter Roberson
Walter Roberson 2020-11-17
Ran in:

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Ran in:
columnTen = struct('fx', rand(7,20)).fx(:,10) %needs R2019b or later IIRC
columnTen = 7×1
0.9090 0.8635 0.0364 0.2788 0.2503 0.1882 0.7757
●
columnTen = subsref(rand(7,20), substruct('()', {':', 10}))
columnTen = 7×1
0.3391 0.0112 0.5269 0.0961 0.5855 0.0371 0.4590
●
But if you are permitted an initialization beforehand:
Col = @(M,n) M(:,n); %once
ColumnTen = Col(rand(7,20), 10)

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Sinan Islam
Sinan Islam 2020-11-18
Verbose but working. I hope MATLAB make it as simple as other languages. Thank you!

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Andrei Bobrov
Andrei Bobrov 2020-11-17

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Y = f(x);
columnTen = Y(:,10);

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Sinan Islam
Sinan Islam 2020-11-17
That is two steps. I need to make the assignment on the fly, in just one line (one operation). I am working with characters. I dont have the option to work on multiple lines (multiple operations). But thanks anyway!

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