[python] Python - AttributeError: 'numpy.ndarray' object has no attribute 'append'

This is related to my question, here.

I now have the updated code as follows:

import numpy as np
import _pickle as cPickle
from PIL import Image
import sys,os

pixels = []
labels = []
traindata = []
i = 0

directory = 'C:\\Users\\abc\\Desktop\\Testing\\images'
for root, dirs, files in os.walk(directory):
    for file in files:
        floc = file
        im = Image.open(str(directory) + '\\' + floc)
        pix = np.array(im.getdata())
        pixels.append(pix)
        labels.append(1)
        pixels = np.array(pixels)
        labels = np.array(labels)
        traindata.append(pixels)
        traindata.append(labels)
        traindata = np.array([traindata[i][i],traindata[1]], dtype=object)
        i = i + 1

# do the same for validation and test data
# put all data and labels into 'data' array
cPickle.dump(traindata,open('data.pickle','wb'))

FILE = open("data.pickle", 'rb')
content = cPickle.load(FILE)
print (content)

When having only one image, the code runs fine. But, when I add another image or more, I get the following:

Traceback (most recent call last):
  File "pickle_data.py", line 17, in <module>
    pixels.append((pix))
AttributeError: 'numpy.ndarray' object has no attribute 'append'

How can I solve this issue?

Thanks.

Numpy arrays do not have an append method. Use the Numpy append function instead:

import numpy as np

array_3 = np.append(array_1, array_2, axis=n)
# you can either specify an integer axis value n or remove the keyword argument completely

For example, if array_1 and array_2 have the following values:

array_1 = np.array([1, 2])
array_2 = np.array([3, 4])

If you call np.append without specifying an axis value, like so:

array_3 = np.append(array_1, array_2)

array_3 will have the following value:

array([1, 2, 3, 4])

Else, if you call np.append with an axis value of 0, like so:

array_3 = np.append(array_1, array_2, axis=0)

array_3 will have the following value:

 array([[1, 2],
        [3, 4]]) 

More information on the append function here: https://docs.scipy.org/doc/numpy/reference/generated/numpy.append.html

pixels = np.array(pixels) in this line you reassign pixels. So, it may not a list anyhow. Though pixels is not a list it has no attributes append. Does it make sense?

append on an ndarray is ambiguous; to which axis do you want to append the data? Without knowing precisely what your data looks like, I can only provide an example using numpy.concatenate that I hope will help:

import numpy as np

pixels = np.array([[3,3]])
pix = [4,4]
pixels = np.concatenate((pixels,[pix]),axis=0)

# [[3 3]
#  [4 4]]