1. numpy.random.shuffle(x)
Modify a sequence in-place by shuffling its contents. This function only shuffles the array along the first axis of a multi-dimensional array. The order of sub-arrays is changed but their contents remains the same. Parameters: x : array_like. The array or list to be shuffled. Returns: None
注意：
- 無返回值，改變原有 array
- 對於多維 array，只 shuffle 第一維
2. numpy.random.permutation(x)
Randomly permute a sequence, or return a permuted range. If x is a multi-dimensional array, it is only shuffled along its first index. Parameters: x : int or array_like If x is an integer, randomly permute np.arange(x). If x is an array, make a copy and shuffle the elements randomly. Returns: out : ndarray Permuted sequence or array range.
注意：
- 跟 shuffle 的區別
- 有返回值
- 且不改變原來的 array，會生成一個新的 array
- x 為整型時，先將 x 變成 array： np.arange(x)，再打亂順序
