Numpy陣列操作

變形

• numpy.ndarray.shape表示陣列的維度，返回一個元組，這個元組的長度就是維度的數目，即 ndim 屬性(秩)
• numpy.ndarray.flat 將陣列轉換為一維的迭代器，可以用for訪問陣列每一個元素。
• numpy.ndarray.flatten([order=‘C’]) 將陣列的副本轉換為一維陣列，並返回。

轉置

• numpy.transpose(a, axes=None) Permute the dimensions of an array.
• numpy.ndarray.T Same as self.transpose(), except that self is returned if self.ndim < 2.

維度

• numpy.newaxis = None None的別名，對索引陣列很有用。
• numpy.squeeze(a, axis=None) 從陣列的形狀中刪除單維度條目，即把shape中為1的維度去掉。

組合

• numpy.concatenate((a1, a2, …), axis=0, out=None) Join a sequence of arrays along an existing axis.
• numpy.stack(arrays, axis=0, out=None)Join a sequence of arrays along a new axis.
• numpy.vstack(tup)Stack arrays in sequence vertically (row wise).
• numpy.hstack(tup)Stack arrays in sequence horizontally (column wise).

拆分

• numpy.split(ary, indices_or_sections, axis=0) Split an array into multiple sub-arrays as views into ary.
• numpy.vsplit(ary, indices_or_sections) Split an array into multiple sub-arrays vertically (row-wise).
• numpy.hsplit(ary, indices_or_sections) Split an array into multiple sub-arrays horizontally (column-wise).

平鋪

• numpy.tile(A, reps) Construct an array by repeating A the number of times given by reps.
• numpy.repeat(a, repeats, axis=None) Repeat elements of an array.

增刪

• numpy.unique(ar, return_index=False, return_inverse=False,return_counts=False, axis=None) Find the unique elements of an array.