I know this question has been asked before but I can't seem to get mine to work.
import numpy as np
def load_dataset(): def download(filename, source=""): print ("Downloading ",filename) import urllib urllib.urlretrieve(source+filename,filename) import gzip def load_mnist_images(filename): if not os.path.exists(filename): download(filename) with gzip.open(filename,"rb") as f: data=np.frombuffer(f.read(), np.uint8, offset=16) data = data.reshape(-1,1,28,28) return data/np.float32(256) def load_mnist_labels(filename): if not os.path.exists(filename): download(filename) with gzip.open(filename,"rb") as f: data = np.frombuffer(f.read(), np.uint8, offset=8) return data X_train = load_mnist_images("train-images-idx3-ubyte.gz") y_train = load_mnist_labels("train-labels-idx1-ubyte.gz") X_test = load_mnist_images("t10k-images-idx3-ubyte.gz") y_test = load_mnist_labels("t10k-labels-idx1-ubyte.gz") return X_train, y_train, X_test, y_test
X_train, y_train, X_test, y_test = load_dataset()
import matplotlib
matplotlib.use("TkAgg")
import matplotlib.pyplot as plt
plt.show(plt.imshow(X_train[3][0]))This is the error I am getting:
Traceback (most recent call last): File "C:\Users\nehad\Desktop\Neha\Non-School\Python\Handwritten Digits
Recognition.py", line 38, in <module> X_train, y_train, X_test, y_test = load_dataset()
TypeError: cannot unpack non-iterable NoneType objectI am new to machine learning. Did I just miss something simple? I am trying a Handwritten Digit Recognition project for my school Science Exhibition.
15 Answers
You get this error when you perform a multiple assignment to None (which is of NoneType). For instance:
X_train, y_train, X_test, y_test = NoneTypeError: cannot unpack non-iterable NoneType object
So if you get this, the error is most likely that the right-hand part of the assignment is not what you expected (it's nothing).
1I think your X_train, y_train, X_test, y_test are defined inside your load_mnist_imagesfunction, and are thus not defined for your load_dataset function.
You should de-indent your 5 lines from X_train = ... to return X_train, ... and your code might work better then.
Splitting/breaking multiple assignment to None resolves this issue.
e.g. This DOESN'T work:
test_set_raw, test_set_transformed, train_set_raw, train_set_transformed = NoneThis DOES work (no error):
test_set_raw = None
test_set_transformed = None
train_set_raw = None
train_set_transformed = NoneYou get that error because load_dataset() returns None.
run this and you get the same error:
X_train, y_train, X_test, y_test = NoneIn your code: plt.show(plt.imshow(X_train[3][0])) Add: coma before the last closing bracket, this error is showing because you're using a tuple and tuple receive coma after the last element or item in it. Do this: plt.show(plt.imshow(X_train[3][0]),)
