numpy基本操作

1. 基本操作

import numpy as np

# print(dir(np))

# 1D array
arr1 = np.array([1,2,3,4,5,6,7,8])
# 2D array
arr2 = np.array([[1,2,3,4],[5,6,7,8]])
# 3D array
arr3 = np.array([[[1,2],[3,4]],[[5,6],[7,8]]])

# 数据类型
print(type(arr1))
# 维度
print(arr1.ndim)
# 形状
print(arr1.shape)
# 元素个数
print(arr1.size)
# 元素类型
print(arr1.dtype)
# 重新设置数据类型
arr1 = arr1.astype('float32')
print(arr1.dtype)   
# 重新设置形状
print(arr1.reshape(