为什么plt.imshow()不显示图像? [英] Why plt.imshow() doesn't display the image?

问题描述

我是keras的新手，当我尝试在Linux上运行我的第一个keras程序时，事情并没有如我所愿. 这是我的python代码:

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])

最后一句不显示任何内容.我从教程中复制了这些代码，没有进行任何修改.我的计算机上的matplotlib后端没有任何问题.我已经通过下面的代码进行了测试.

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()

然后我得到了这样的图像:

And then I got a image like that:

而且，我可以打印X_train [0]，这似乎没什么问题.
那么，这可能是什么原因呢?为什么我的第一个代码中的imshow()函数没有显示任何内容?

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?

推荐答案

解决方案就像在代码段末尾添加plt.show()一样简单:

The solution was as simple as adding plt.show() at the end of the code snippet:

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()

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