Indexed Assignment on the Right Side

2 次查看（过去 30 天）
Sinan Islam
Sinan Islam 2020-11-17
评论： Sinan Islam 2020-11-18
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.

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2020-11-17
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)
  1 个评论
Sinan Islam
Sinan Islam 2020-11-18
Verbose but working. I hope MATLAB make it as simple as other languages. Thank you!

请先登录，再进行评论。

更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2020-11-17
Y = f(x);
columnTen = Y(:,10);
  1 个评论
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!

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by