添加2d数组以在python中制作3d

Question

I have a requirement to read image files( 28*28) from a folder and stack them together to make a single array for analysis.

I have the following code:

for fname in os.listdir(dirname):
    im = Image.open(os.path.join(dirname, fname))
    imarray = np.array(im)
    final = np.stack((final,imarray ), axis = 0)

am getting the following error: ValueError: all input arrays must have the same shape

imarray is (28,28) and i have 60K images in that folder so i want to make a array of size (60000,28,28)

Thanks for the help NK

Answer 1

Build a list of all components and stack them once:

alist = []
for fname in os.listdir(dirname):
    im = Image.open(os.path.join(dirname, fname))
    imarray = np.array(im)
    alist.append(imarray)
final = np.stack(alist)   # axis=0 is the default

This will join them on a new initial axis.