python讀取二進制mnist
阿新 • • 發佈:2017-05-31
ray set esc bit lena des unsigned pen ...
training data 數據結構:
[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
將整個文件讀入:
filename = ‘train-images.idx3-ubyte‘ binfile = open(filename , ‘rb‘) buf = binfile.read()
讀取頭四個32bit的interger:
index = 0 magic, numImages , numRows , numColumns = struct.unpack_from(‘>IIII‘ , buf , index) index += struct.calcsize(‘>IIII‘)
讀取一個圖片,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()
python讀取二進制mnist