Does anyone familiar with the Iris data set? Please correct me if I am wrong, but this data set has 4 dimensions. However, ndims returns only 2. How is that possible?
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where from did you obtain the dataset? how is it stored? – Schorsch May 27 '13 at 16:29
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Features and dimensions mean slightly different things in the machine learning and programming worlds, respectively. – Ansari May 27 '13 at 16:53
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It has 2 dimensions, one of length 150 and the other of length 4 (not including Species data). Perhaps you want to use size instead of ndims?
James
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size will return 150 4. which corresponds to your answer above. I just still do not understand why does dimension equal to 2? I have tried searching for the meaning of the dimensions. It does tell me that, dimension is quite similar with an array. – dee May 27 '13 at 18:42
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@dee You can add an additional parameter to your `size` call to get just the number of columns, ie `size(iris,2)`. `ndims` gives the number of dimensions of the array, ie the dimensionality of the "hypercube" it can conceptualised as. This is obviously pretty meaningless for a flat database, as the answer will always be 2. – James May 28 '13 at 09:37