How do I evaluate a function within a string such as 'sin(x)' for given x values?

2014 5 1
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更新时间：2014 5 1
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I am making a program which allows for user input of different functions. I made a dialog box with inputdlg, but the result was a string and I cant figure out how to evaluate the given function numerically.
This is the input part of the code so far. What am I doing wrong?
func=inputdlg('Input Function: y=') func1=str2num(func)
I have also tried using eval()
func=inputdlg('Input Function: y=') func1=eval(func)
My goal is that when someone inputs sin(x), the result is func='sin(x)' and func1 is sin(x) evaluated for the x-values.
Thanks!

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Star Strider
Star Strider 2014-5-1

1 个投票

This will get you started:
func = inputdlg('Input function y = ')
fh = str2func(char(func))
y = fh(pi/6)
The str2func function is under ‘Function Handles’ in the documentation. (I had to search for it.)

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