create vector in for loop and then need to store vector in a matrix one after another

Question

Muhammad Asad 2022-4-22

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1702490-create-vector-in-for-loop-and-then-need-to-store-vector-in-a-matrix-one-after-another

评论： Rik 2022-4-23

I want to create a code in double for loop shown below. When vector "v" creates in first run then its store values but when internal "for loop" increaed the value of b by 0.1 then previous values in vector v replaced. I need both values and i don,t understand how i get?

Every time value changed i need. I want to store values in a matrix means first run stores in first row, then value increment in internal for loop then this valus agiain stored ina matrix and so on. at the end i need all combinations in a matrix.

Can anyone give me a suitable suggestion? thanks in advance

clear all

for a=1:0.1:2

k1=a

for b=1:0.1:2

k2=b;

v=[k1 k2]

newtable=array2table(v)

end

1 个评论
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Rik 2022-4-22

You aren't using any indexing. I suggest you have a look at the relevant chapter of the Onramp tutorial.

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Answer 1

Voss 2022-4-22

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https://ww2.mathworks.cn/matlabcentral/answers/1702490-create-vector-in-for-loop-and-then-need-to-store-vector-in-a-matrix-one-after-another#answer_948580

在 MATLAB Online 中打开

Is this what you mean?

clear all
v = [];
for a=1:0.1:2
    k1=a;
    for b=1:0.1:2
        k2=b;
        v(end+1,:)=[k1 k2];
    end
end
disp(v);
0000    1.0000
0000    1.1000
0000    1.2000
0000    1.3000
0000    1.4000
0000    1.5000
0000    1.6000
0000    1.7000
0000    1.8000
0000    1.9000
0000    2.0000
1000    1.0000
1000    1.1000
1000    1.2000
1000    1.3000
1000    1.4000
1000    1.5000
1000    1.6000
1000    1.7000
1000    1.8000
1000    1.9000
1000    2.0000
2000    1.0000
2000    1.1000
2000    1.2000
2000    1.3000
2000    1.4000
2000    1.5000
2000    1.6000
2000    1.7000
2000    1.8000
2000    1.9000
2000    2.0000
3000    1.0000
3000    1.1000
3000    1.2000
3000    1.3000
3000    1.4000
3000    1.5000
3000    1.6000
3000    1.7000
3000    1.8000
3000    1.9000
3000    2.0000
4000    1.0000
4000    1.1000
4000    1.2000
4000    1.3000
4000    1.4000
4000    1.5000
4000    1.6000
4000    1.7000
4000    1.8000
4000    1.9000
4000    2.0000
5000    1.0000
5000    1.1000
5000    1.2000
5000    1.3000
5000    1.4000
5000    1.5000
5000    1.6000
5000    1.7000
5000    1.8000
5000    1.9000
5000    2.0000
6000    1.0000
6000    1.1000
6000    1.2000
6000    1.3000
6000    1.4000
6000    1.5000
6000    1.6000
6000    1.7000
6000    1.8000
6000    1.9000
6000    2.0000
7000    1.0000
7000    1.1000
7000    1.2000
7000    1.3000
7000    1.4000
7000    1.5000
7000    1.6000
7000    1.7000
7000    1.8000
7000    1.9000
7000    2.0000
8000    1.0000
8000    1.1000
8000    1.2000
8000    1.3000
8000    1.4000
8000    1.5000
8000    1.6000
8000    1.7000
8000    1.8000
8000    1.9000
8000    2.0000
9000    1.0000
9000    1.1000
9000    1.2000
9000    1.3000
9000    1.4000
9000    1.5000
9000    1.6000
9000    1.7000
9000    1.8000
9000    1.9000
9000    2.0000
0000    1.0000
0000    1.1000
0000    1.2000
0000    1.3000
0000    1.4000
0000    1.5000
0000    1.6000
0000    1.7000
0000    1.8000
0000    1.9000
0000    2.0000

5 个评论
显示 3更早的评论隐藏 3更早的评论

Voss 2022-4-22

在 MATLAB Online 中打开

The end keyword in an indexing expression refers to the last index of the dimension it's used. So v(end,:) refers to the last row of v, and v(end+1,:) would refer to the row one beyond the last row. In this expression:

v(end+1,:)=[k1 k2 k3]

[k1 k2 k3] is assigned to the row one beyond the last row of v, so the effect is to add a new row to the end of v containing [k1 k2 k3].

About the Simulink block question, I don't know. I've never used Simulink. Maybe ask a new question about it and post the latest version of your code in the new question.

Rik 2022-4-23

Some comments:

You should avoid clear all. You never actually need it. Using clear or clearvars instead is almost always enough for a debugging script. For actual use, you should be using a function, which will always start out with a clean workspace.

You should try to determine the size of your array based on your variables. That way you can pre-allocate the entire array, which avoids data copying when extending the array, and will also give you an early warning if there are memory issues.

I strongly suggest to do the Onramp tutorial. It is really worth the investment to learn the tool you're using.

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