How to print symbolic representation of [4^1+1 4^2+1 4^3+1] rather than the actual numerical output?

Question

hmhuang 2020-5-17

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https://ww2.mathworks.cn/matlabcentral/answers/526138-how-to-print-symbolic-representation-of-4-1-1-4-2-1-4-3-1-rather-than-the-actual-numerical-output

评论： Ameer Hamza 2020-5-18

采纳的回答： Ameer Hamza

在 MATLAB Online 中打开

I would like to add a line of texts like "points = 4^1+1 4^2+1 4^3+1" instead of "points = 5 17 65" to chart.

The current content of my code to print "points = 5 17 65" is as following:

for i = 1:3
    n = 4^i + 1;
    %{
        do something with numeric values of n and i (i.e., i = 1, 2, 3)
    %}
    
    % Storing "number of points" in vector 'point'
    point(i) = n;
end
disp(['Grid points = ' sprintf('%d ', point)])

Note that I do need the numerical values of n and i (i.e., i = 1, 2, 3 for n = 4^i + 1) to do some computations.

I found

syms i

may be appropriate for my intended use, but cannot figure out how to exactly apply it into my for-loop.

Please help me to figure out, any suggestions will be very appreciated!

Thanks!

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Answer 1

Ameer Hamza 2020-5-17

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/526138-how-to-print-symbolic-representation-of-4-1-1-4-2-1-4-3-1-rather-than-the-actual-numerical-output#answer_432966

编辑：Ameer Hamza 2020-5-17

在 MATLAB Online 中打开

point = 1:3;
disp(['Grid points = ' sprintf('4^%d ', point)])

Result

Grid points = 4^1 4^2 4^3

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hmhuang 2020-5-18

在 MATLAB Online 中打开

Thanks for your solution! Very intuitive!

But If I want add the text "Grid points = 4^1 4^2 4^3" to a chart by using:

for i = 1:3
    n = 4^i + 1;
    %{
        do something with numeric values of n and i (i.e., i = 1, 2, 3)
    %}
    
    % Storing "number of points" in vector 'point'
    point(i) = sprintf("4^%d", i);
end
txt = { "Resolution",
        ["Grid points = " point] };
text(xlim(1)*2, ylim(2)*0.01, txt, 'FontSize', 16);

An error happened due to the misuse of cell array:

Error using text
Cell array can contain only non-empty character vectors, string vectors, or numbers.

How can I resolve this problem?

Thank you

Ameer Hamza 2020-5-18

The syntax is not correct, according to MATLAB. But I didn't understand what you are trying to do here. Can you explain with an image what where you want to write the text()?

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