直接看代碼例子，有詳細注釋??！
import tensorflow as tf import numpy as np d = np.arange(0,60).reshape([6, 10]) # 將array轉化為tensor data = tf.data.Dataset.from_tensor_slices(d) # 從data數據集中按順序抽取buffer_size個樣本放在buffer中，然后打亂buffer中的樣本 # buffer中樣本個數不足buffer_size，繼續從data數據集中安順序填充至buffer_size， # 此時會再次打亂 data = data.shuffle(buffer_size=3) # 每次從buffer中抽取4個樣本 data = data.batch(4) # 將data數據集重復，其實就是2個epoch數據集 data = data.repeat(2) # 構造獲取數據的迭代器 iters = data.make_one_shot_iterator() # 每次從迭代器中獲取一批數據 batch = iters.get_next() sess = tf.Session() sess.run(batch) # 數據集完成遍歷完之后，繼續抽取的話會報錯：OutOfRangeError
In [21]: d Out[21]: array([[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [30, 31, 32, 33, 34, 35, 36, 37, 38, 39], [40, 41, 42, 43, 44, 45, 46, 47, 48, 49], [50, 51, 52, 53, 54, 55, 56, 57, 58, 59]]) In [22]: sess.run(batch) Out[22]: array([[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [30, 31, 32, 33, 34, 35, 36, 37, 38, 39], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19]]) In [23]: sess.run(batch) Out[23]: array([[40, 41, 42, 43, 44, 45, 46, 47, 48, 49], [50, 51, 52, 53, 54, 55, 56, 57, 58, 59]])
從輸出結果可以看出：
shuffle是按順序將數據放入buffer里面的；
當repeat函數在shuffle之后的話，是將一個epoch的數據集抽取完畢，再進行下一個epoch的。
那么，當repeat函數在shuffle之前會怎么樣呢？如下：
data = data.repeat(2) data = data.shuffle(buffer_size=3) data = data.batch(4)
In [25]: sess.run(batch) Out[25]: array([[10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]]) In [26]: sess.run(batch) Out[26]: array([[50, 51, 52, 53, 54, 55, 56, 57, 58, 59], [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [30, 31, 32, 33, 34, 35, 36, 37, 38, 39], [30, 31, 32, 33, 34, 35, 36, 37, 38, 39]]) In [27]: sess.run(batch) Out[27]: array([[10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [50, 51, 52, 53, 54, 55, 56, 57, 58, 59], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]])
可以看出，其實它就是先將數據集復制一遍，然后把兩個epoch當成同一個新的數據集，一直shuffle和batch下去。
以上這篇TensorFlow dataset.shuffle、batch、repeat的使用詳解就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支持億速云。
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