Indexing directly on a matrix literal

Question

Bill Tubbs 2020-2-3

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/503476-indexing-directly-on-a-matrix-literal

回答： Divya Yerraguntla 2020-2-6

I'm assuming it's not possible in MATLAB to index directly on a matrix literal.

For example: Say I want to show the first 5 rows of all these vectors:

>> [t_sim, u_sim, y_sim, y_data](1:5,:)
 [t_sim, u_sim, y_sim, y_data](1:5,:)
                              ↑
Error: Invalid expression. When calling a function or indexing a variable, use
parentheses. Otherwise, check for mismatched delimiters.

This works of course but requires an extra line and creating a variable:

>> temp = [t_sim, u_sim, y_sim, y_data];
>> temp(1:5,:)
ans =
         0   -1.0000         0    0.3565
    1.0000    1.0000   -0.9614    1.4867
    2.0000   -1.0000   -0.6378   -1.5364
    3.0000    1.0000   -1.2231    0.0902
    4.0000    1.0000   -0.5430   -0.4092
    
>> clear temp

Presumably the MATLAB language is not parsed in a way that indexing is applied to "whatever comes before". Does that mean you can only index on a variable as above?

Can someone please confirm?