string from a textbox

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abdullah ek 2018-7-4

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https://ww2.mathworks.cn/matlabcentral/answers/408831-string-from-a-textbox

评论： Paolo 2018-7-5

hi. i want to extract 4,5,6,5 from string 4x^3 + 5x^2 + 6x^1 + 5

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Answer 1

Paolo 2018-7-4

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https://ww2.mathworks.cn/matlabcentral/answers/408831-string-from-a-textbox#answer_327509

编辑：Paolo 2018-7-4

在 MATLAB Online 中打开

 str = '4x^3 + 5x^2 + 6x^1 + 5'
 num = regexp(str,'(?<!\^)(\d)','match');

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abdullah ek 2018-7-5

i also want to extract the missing cofficients i am using the function sym2pol like syms x c = sym2poly(x^3 - 2*x - 5); but i dont know how to convert my value from textbox into symbolic polynomial which can be placed in sym2poly function.

Paolo 2018-7-5

What missing coefficients? I don't see any for the equation you shared. Perhaps you need to use str2sym to convert the string to a symbolic expression before you can use sym2pol or coeffs as suggested by Stephen. I am unable to test it for you because of this bug.

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