# How can I override a value with an input?

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Andrew on 8 Aug 2014
Answered: Geoff Hayes on 8 Aug 2014
I have a list of variables with values, but I want to be able to override one of those values with an input. To demonstrate:
function [output] = test(variable, value)
x = 2;
y = 3;
q = 10;
end
And let's say my input is (x, 5). Other than using a bunch of if statements, is there a way to make x = 5?
##### 2 CommentsShowHide 1 older comment
Andrew on 8 Aug 2014
That's the thing, I don't know how to use them. 'variable' should match one of the ones declared in the code (i.e. x, y, or q) and 'value' is whatever value that variable should be. So if my input is (y, 10), then I want to set y = 10.
I'm explaining this poorly, I apologize, but I'm not quite sure how else to describe it.

A Jenkins on 8 Aug 2014
Some of it depends on how much you want to protect against "bad" values or variable names being passed. But here is a simple trick:
function [output] = test(variable, value)
mydata.x = 2;
mydata.y = 3;
mydata.q = 10;
mydata.(variable)=value
end
........................................................
>> test('x',5)
mydata =
x: 5
y: 3
q: 10
Andrew on 8 Aug 2014
Yeah, that should work, thanks!

Geoff Hayes on 8 Aug 2014
Could also just compare the input variable to a set of pre-defined "matches"
function [output] = test(variable, value)
x = 2;
y = 3;
q = 10;
if ischar(variable) && isvector(variable)
if strcmp(variable,'x')
x = value;
elseif strcmp(variable,'y')
y = value;
elseif strcmp(variable,'q')
q = value;
end
end
The above will guard against the case where variable is not a string, and is one of x, y, and q.

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