List of List to ndarray

Question

I am trying to use kmeans clustering in scipy, exactly the one present here: http://docs.scipy.org/doc/scipy/reference/generated/scipy.cluster.vq.kmeans.html#scipy.cluster.vq.kmeans What I am trying to do is to convert a list of list such as the following: ``` data without_x[ [0, 0, 0, 0, 0, 0, 0, 20.0, 1.0, 48.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1224.0, 125.5, 3156.0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 22.5, 56.0, 41.5, 85.5, 0, 0, 0, 0, 0, 0, 0, 0, 1495.0, 3496.5, 2715.0, 5566.5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ] ``` into a ndarry in order to use it with the Kmeans method. When I try to convert the list of list into the ndarray I get an empty array, thus voiding the whole analysis. The length of the ndarray is variable and it depends on the number of samples gathered. But I can get that easily with the len(data_without_x) Here is a snippet of the code that returns the empty list. ``` import numpy as np import "other functions" data, data_without_x = da…

Accepted Answer

That is exactly how to convert a list of lists to an ndarray in python. Are you sure your `data_without_x` is filled correctly? On my machine:

```
data = [[1,2,3,4],[5,6,7,8]]
data_arr = np.array(data)

data_arr
array([[1,2,3,4],
       [5,6,7,8]])
```

Which is the behavior I think you're expecting

Looking at your input you have a lot of zeros...keep in mind that the print out doesn't show all of it. You may just be seeing all the "zeros" from your input. Examine a specific non zero element to be sure

List of List to ndarray

Solution

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