Why plt.imshow() doesn't display the image?

Question

I am a newbie to keras, and when I tried to run my first keras program on my linux, something just didn't go as I wish. Here is my python code:

import numpy as np

np.random.seed(123)

from keras.models import Sequential

from keras.layers import Dense, Dropout, Activation, Flatten 

from keras.layers import Convolution2D, MaxPooling2D

from keras.utils import np_utils

from keras.datasets import mnist 

(X_train,y_train),(X_test,y_test) = mnist.load_data()

print X_train.shape

from matplotlib import pyplot as plt

plt.imshow(X_train[0])

The last sentence doesn't display anything. I copied those codes from a tutorial with out any modification. And there is nothing wrong with the backend of matplotlib on my computer. I have tested that through the code below.

import matplotlib.pyplot as plt

data = [[0, 0.25], [0.5, 0.75]]

fig, ax = plt.subplots()

im = ax.imshow(data, cmap=plt.get_cmap('hot'), interpolation='nearest', vmin=0, vmax=1)

fig.colorbar(im)

plt.show()

And then I got an image like that:

Moreover, I can get X_train[0] printed and it seems nothing wrong.

So what could be the reason for that? Why the imshow() function in my first code didn't display anything?

Answer 1

You can use below-mentioned code to display the image where by adding plt.show() at the end of the code can help:-

import numpy as np

np.random.seed(123)

from keras.models import Sequential

from keras.layers import Dense, Dropout, Activation, Flatten 

from keras.layers import Convolution2D, MaxPooling2D

from keras.utils import np_utils

from keras.datasets import mnist 

(X_train,y_train),(X_test,y_test) = mnist.load_data()

print X_train.shape

from matplotlib import pyplot as plt

plt.imshow(X_train[0])

plt.show()

To know more about this you can have a look at the following video tutorial:-