读书笔记 numpy入门 第2章 数据属性

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https://github.com/jakevdp/PythonDataScienceHandbook

NumPy数组的属性

  • ndim 数组的维度
  • shape 数组每个维度的大小
  • size 数组的总大小
  • dtype 数组的数据类型
  • itemsize 每个数组元素字节的大小
  • nbytes 数组总字节大小的属性

用例子体会

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import numpy as np
np.random.seed(0)

x1 = np.random.randint(10, size=6)  # 一维数组
x2 = np.random.randint(10, size=(3, 4))  # 二维数组
x3 = np.random.randint(10, size=(3, 4, 5))  # 三维数组

print("x3 ndim: ", x3.ndim)
print("x3 shape:", x3.shape)
print("x3 size: ", x3.size)

>>> x3 ndim:  3
>>> x3 shape: (3, 4, 5)
>>> x3 size:  60

print("dtype:", x3.dtype)

>>>dtype: int64

print("itemsize:", x3.itemsize, "bytes")
print("nbytes:", x3.nbytes, "bytes")

>>> itemsize: 8 bytes
>>> nbytes: 480 bytes