How do I extract a vector from a single field in a structured variable?

Question

Marissa Holden 2022-1-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1630845-how-do-i-extract-a-vector-from-a-single-field-in-a-structured-variable

编辑： Stephen23 2022-1-18

I am trying to create a vector variable from a field of an 8x1 structure.

To create the structure I used the dir function - I am trying to create a vector of subfolders name and set the code up so that it can take out the names if different folders were in the original folder.

I type:

folders_temp = dir('data_CLEANED');

folder_names = folders_temp(~ismember({folders_temp.name},{'.','..'})); %just doing this to get rid of dot and dot dot

participant_ID = [folder_names.name]

The participant names all crammed together in a single cell

Is there a way to create a vector with each participant code having its own cell?

4 个评论
显示 2更早的评论隐藏 2更早的评论

Voss 2022-1-18

Use {} rather than [], like in my answer.

Stephen23 2022-1-18

编辑：Stephen23 2022-1-18

"... when I want it to return [MH, TM, JW]"

In MATLAB square brackets are a concatenation operator, not a list operator like in some other languages.

What you need is a cell array, just as Benjamin shows: https://www.mathworks.com/help/matlab/cell-arrays.html

You might find these informative too: https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Voss 2022-1-18

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1630845-how-do-i-extract-a-vector-from-a-single-field-in-a-structured-variable#answer_876385

在 MATLAB Online 中打开

Maybe this?

folder_names = struct('name',{'a','bb','ccc'})
folder_names = 1×3 struct array with fields:
    name
participant_ID = {folder_names.name}
participant_ID = 1×3 cell array
    {'a'}    {'bb'}    {'ccc'}