making a function that uses a string input

Question

Sean Smith 2011-10-20

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/18912-making-a-function-that-uses-a-string-input

I am trying to make a function:

function [y]=my_function(A,B,C)

where A is a string and B and C are just numbers. If someone enters 'yes' for A then a number for B and C I want it to do one calculation. If someone enters 'no' for A then numbers for B and C I want it to do another calculation. I was trying to use if statements i.e.

if A='yes'
calculations
end
if A='no'
calculations
end

but I can't get the function to accept strings and then use them with the if statements. Is there a way to do this or am I way off? Thanks. Let me know if I wasn't clear with something.

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Answer 1

Walter Roberson 2011-10-20

4
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https://ww2.mathworks.cn/matlabcentral/answers/18912-making-a-function-that-uses-a-string-input#answer_25276

在 MATLAB Online 中打开

if A='yes'

attempts to assign 'yes' to A in the middle of the 'if' statement. This is... not good.

if A=='yes'

would attempt to compare A to 'yes'. Which will work if A happens to be a row vector with exactly three elements (the same size as 'yes'), but will fail with a dimension mismatch if A happens to be a different size, such as if A is a row vector with two elements containing 'no' . Using '==' to compare strings is thus not recommended.

For your situation, I would suggest you use strcmpi()