How do I insert many variables(upto 100) into one function?

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Hoon 2014-2-25

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评论： Walter Roberson 2014-2-25

采纳的回答： Rick Rosson

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I have variables with value

B1=1 B2=2 B3=4 B4 ... B100= some number

(it goes on to 100 variables)

then I want to insert all of these variables into one function

save('filename.mat', 'B1', 'B2', 'B3'.... 'B100')

However, it will be very counterproductive to write all the 100 variables...

how do i shorten this function?

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John D'Errico 2014-2-25

Perhaps this is a good time for you to learn NOT to name all of your variables like that, and instead learn how to use a vector. Vectors are new things in MATLAB, I think introduced in version 1 of the software, so really rather new.

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Answer 1

Rick Rosson 2014-2-25

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B = zeros(100,1);
B(1) = 1;
B(2) = 2;
B(3) = 4;
B(4) = ...
B(5) = ...
...
...
B(100) = ...
save('filename.mat', 'B');

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Hoon 2014-2-25

hmm... I think I haven't specified my question in detail. in my real program, each variable will hold vectors of different size.

Your answer seems like concaternating all the variables, so maybe I should save concaternated values and load each column.

conclusively I should concern more about separating columns of saved value. Thank you for your approach.

Walter Roberson 2014-2-25

If the vectors are different sizes then you could use a cell array.

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Answer 2

Star Strider 2014-2-25

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This seems a bit inelegant but it works:

B1=1; B2=2; B3=4;
for k1 = 1:3
    B(k1) = eval(sprintf('B%d', k1));
end

You would then save vector B in your save command.

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Hoon 2014-2-25

sorry, but I want to load each variables once i saved them...

but i have to think otherwise

Star Strider 2014-2-25

编辑：Star Strider 2014-2-25

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You can always refer to them by their subscripts, since those correspond to the names you’ve given the original variables.

With respect to vector B:

B(1) = B1;
B(2) = B2;
    .
    .
    .
B(100) = B100;

Then, for example, refer to B(1) in your code rather than B1, etc.

Unless there is some problem with this (creating a vector B out of the original set of B variables) that you are not telling us about, this is not only easier to work with but much more efficient.

If the B variables are instead vectors of different lengths, and you are having problems creating a matrix from them, MATLAB can do that very efficiently with cell arrays.

We need to know what you want to do in much more detail, and specifically why creating the B vector does not work for you.

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Answer 3

Walter Roberson 2014-2-25

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save('filename.mat', 'B\d+')

This syntax is not well documented in the save() document. It is just barely hinted at: notice that there is an entry for "regular expression" in the Tips section of the page.