[l m]=a(1,2,3;6,7,8) in matlab..........

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KALYANAPU SRINIVAS 2017-5-10

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评论： Stephen23 2017-5-10

is it possible to assign the elements of matrix a to [l m]?

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KALYANAPU SRINIVAS 2017-5-10

in the above question l=a[i][j] value i.e l=1 and m=a[i][j+1] value i.e m=6; and so on..... is the required answer. Please provide the code if exist

Jan 2017-5-10

The question is not clear and the comment confuses me even more. What is "a[i][j]"? It is no valid Matlab syntax, but please do not let us guess if you mean C code or any other notation. Explain clearly what you want to get. "m=a[i][j+1] value i.e m=6"???

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Answer 1

KL 2017-5-10

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在 MATLAB Online 中打开

You cannot assign two variables in one command unless it's a function return.
To define an array you should use "Square braces" --> [ ]
Then if you want to access the elements of a matrix, it goes like matrix_name(rowIndex, columnIndex))

For your case,

>> a = [1,2,3;6,7,8]
a =
       1     2     3
       6     7     8
>> l = a(1,1)
l =
       1
>> m = a(2,1)
m =
       6

In case you want all the values in the first row on l and second row on m, then

>> l = a(1,:)
l =
       1     2     3
>> m = a(2,:)
m =
       6     7     8

here : means all elements in the specified rowIndex.

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KL 2017-5-10

Thanks for the links Stephen. Yes, I'm familar with cell array returns while accessing its contents (as opposed to matrices). I'm just wondering, does it really make a difference calling it array concatenation? after all, we're creating a new array by using the square brackets, I think. Having said that, I appreciate you pushing people learn the better way.

Stephen23 2017-5-10

"does it really make a difference calling it array concatenation?"

We regularly get questions here where people want to create lists (which MATLAB does not have), and they often mistake the [] operator for a list operator. It does cause some confusion for them. I believe that clarifying the concatenation role helps beginners to understand that all numeric values are arrays (even scalar arrays (aka "numbers")), as arrays are a first-class type in MATLAB.

So while the difference might be subtle and small, I think it is a point that is worth making, in order to understand MATLAB better.

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