Python reads binary mnist and python binary mnist

Python reads binary mnist and python binary mnist

Training data Structure:

[offset] [type]          [value]          [description] 0000     32 bit integer  0x00000803(2051) magic number 0004     32 bit integer  60000            number of images 0008     32 bit integer  28               number of rows 0012     32 bit integer  28               number of columns 0016     unsigned byte   ??               pixel 0017     unsigned byte   ??               pixel ........ xxxx     unsigned byte   ??               pixel

 

 

Read the entire file:

filename = 'train-images.idx3-ubyte'binfile = open(filename , 'rb')buf = binfile.read()

 

Read the four 32bit interger headers:

index = 0magic, numImages , numRows , numColumns = struct.unpack_from('>IIII' , buf , index)index += struct.calcsize('>IIII')

 

Read an image, 784 = 28*28:

im = struct.unpack_from('>784B' ,buf, index)index += struct.calcsize('>784B')im = np.array(im)im = im.reshape(28,28)fig = plt.figure()plotwindow = fig.add_subplot(111)plt.imshow(im , cmap='gray')plt.show()