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python学习之numpy.zeros

热度:39   发布时间:2023-12-07 21:21:14.0

一、用法:zeros(shape, dtype=float, order=‘C’)

返回:返回来一个给定形状和类型的用0填充的数组;

二、参数:

1.shape:形状
2.dtype:数据类型,可选参数,默认numpy.float64
dtype类型:

  • t ,位域,如t4代表4位

  • b,布尔值,true or false

  • i,整数,如i8(64位)

  • u,无符号整数,u8(64位)

  • f,浮点数,f8(64位)

  • c,浮点负数,

  • o,对象,

  • s,a,字符串,s24

  • u,unicode,u24

3.order:可选参数,c代表与c语言类似,行优先;F代表列优

三、例子:

  • 1.生成包含5个元素的零矩阵
np.zeros(5)
array([ 0.,  0.,  0.,  0.,  0.])
  • 2.生成包含5个元素的零矩阵,且各元素为整形
np.zeros((5,), dtype=np.int)
array([0, 0, 0, 0, 0])
  • 3.生成2行1列的零矩阵
np.zeros((2, 1))
array([[ 0.],[ 0.]])
  • 4.生成2行2列的零矩阵
s = (2,2)
np.zeros(s)
array([[ 0.,  0.],[ 0.,  0.]])
np.zeros((2,), dtype=[('x', 'i4'), ('y', 'i4')]) # custom dtype
array([(0, 0), (0, 0)],dtype=[('x', '<i4'), ('y', '<i4')])

zeros(shape, dtype=float, order=‘C’)

Return a new array of given shape and type, filled with zeros.

  • Parameters

shape : int or sequence of ints
Shape of the new array, e.g., (2, 3)or 2.
dtype : data-type, optional
The desired data-type for the array, e.g., numpy.int8. Default is
numpy.float64.
order : {‘C’, ‘F’}, optional
Whether to store multidimensional data in C- or Fortran-contiguous
(row- or column-wise) order in memory.

  • Returns

out : ndarray
Array of zeros with the given shape, dtype, and order.

  • See Also

zeros_like : Return an array of zeros with shape and type of input.
ones_like : Return an array of ones with shape and type of input.
empty_like : Return an empty array with shape and type of input.
ones : Return a new array setting values to one.
empty : Return a new uninitialized array.

  • Examples

np.zeros(5)
array([ 0., 0., 0., 0., 0.])

np.zeros((5,), dtype=np.int)
array([0, 0, 0, 0, 0])

np.zeros((2, 1))
array([[ 0.],
[ 0.]])

s = (2,2)
np.zeros(s)
array([[ 0., 0.],
[ 0., 0.]])

np.zeros((2,), dtype=[(‘x’, ‘i4’), (‘y’, ‘i4’)]) # custom dtype
array([(0, 0), (0, 0)],
dtype=[(‘x’, ‘<i4’), (‘y’, ‘<i4’)])
Type: builtin_function_or_method