Definitive answer on the correct str2double behavior for the string '10 20'

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Nicholas 2014-7-9

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评论： Nicholas 2014-7-10

Under Windows 7 with R2014a, str2double('10 20') evaluates to NaN. I believe this is the correct behavior, per the documentation.

A colleague working in a Linux environment with R2014a reports that str2double('10 20') evaluates to an array [10 20].

1. Is this possible (without overloading)? 2. Am I correct that the intended evaluation (without overloading) is NaN?

Thanks so much.

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Answer 1

per isakson 2014-7-10

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编辑：per isakson 2014-7-10

在 MATLAB Online 中打开

"str2double('10 20') evaluates to an array [10 20]." . If that is the case it should be reported as a bug

It should not be possible without overloading
You are correct

I advise against unrestricted use of str2num. It uses eval and ... , e.g.

    >> str2num( 'sin([0:0.8:2*pi])')
    ans =
      0    0.7174    0.9996    0.6755   -0.0584   -0.7568   -0.9962   -0.6313

IMO: sscanf is a better alternative

    >> vec = sscanf( '10 20', '%f' )
    vec =
        10
        20

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Nicholas 2014-7-10

Thanks Per.

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Answer 2

Azzi Abdelmalek 2014-7-9

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编辑：Azzi Abdelmalek 2014-7-9

在 MATLAB Online 中打开

str2num('10 20')

will give an array, maybe that's what your colleague has used

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Nicholas 2014-7-10

Thanks Azzi. Yes, we ended up changing the code to use str2num, to give OS independent results. But I am still curious about: a) the definitive (Mathworks intended) behavior of str2double; and b) whether OS can in fact affect behavior (I don't have a Linux machine here to investigate further).

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