‘list’ object has no attribute ‘shape’

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how to create an array to numpy array?

def test(X, N):
    [n,T] = X.shape
    print "n : ", n
    print "T : ", T

if __name__=="__main__":

    X = [[[-9.035250067710876], [7.453250169754028], [33.34074878692627]], [[-6.63700008392334], [5.132999956607819], [31.66075038909912]], [[-5.1272499561309814], [8.251499891281128], [30.925999641418457]]]
    N = 200
    test(X, N)

I am getting error as

AttributeError: 'list' object has no attribute 'shape'

So, I think I need to convert my X to numpy array?

Use numpy.array to use shape attribute.

>>> import numpy as np
>>> X = np.array([
...     [[-9.035250067710876], [7.453250169754028], [33.34074878692627]],
...     [[-6.63700008392334], [5.132999956607819], [31.66075038909912]],
...     [[-5.1272499561309814], [8.251499891281128], [30.925999641418457]]
... ])
>>> X.shape
(3L, 3L, 1L)

NOTE X.shape returns 3-items tuple for the given array; [n, T] = X.shape raises ValueError.

Alternatively, you can use np.shape(...)

For instance:

import numpy as np

and np.shape(a) will give an output of (3,)

import numpy
X = numpy.array(the_big_nested_list_you_had)

It’s still not going to do what you want; you have more bugs, like trying to unpack a 3-dimensional shape into two target variables in test.

?f you have list, you can print its shape as if it is converted to array

import numpy as np

list object in python does not have ‘shape’ attribute because ‘shape’ implies that all the columns (or rows) have equal length along certain dimension.

Let’s say list variable a has following properties:

a = [[2, 3, 4]
    [0, 1]
    [87, 8, 1]]

it is impossible to define ‘shape’ for variable ‘a’.
That is why ‘shape’ might be determined only with ‘arrays’ e.g.

b = numpy.array([[2, 3, 4]
    [0, 1, 22]
    [87, 8, 1]])

I hope this explanation clarifies well this question.

If the type is list, use len(list) and len(list[0]) to get the row and column.

l = [[1,2,3,4], [0,1,3,4]]

len(l) will be 2.

len(l[0]) will be 4.

Firstly you have to import numpy library (refer code for making a numpy array).
shape only gives the output only if the variable is attribute of numpy library. In other words it must be a np.array or any other data structure of numpy.

import numpy
(2, 2)

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