import numpy as np

# 1.创建一个长度为10的ndarry对象，然后让第三个元素等于1

arr1 = np.zeros(10)
arr1[2] = 1
print(arr1)

# 2.创建10到49的ndarry对象

arr2 = np.arange(10, 50)
print(arr2)

# 3.反转arr2

arr3 = arr2[::-1]
print(arr3)

# 4.使用np.random.random

arr4 = np.random.random((10, 10))
print(arr4)
print(arr4.min())

# 5.(10,10) ndarry 内部全为0 外部全为1

arr5 = np.zeros(100).reshape(10, 10)
# arr5[0] = arr5[-1] = arr5[:, 0] = arr5[:, -1] = 1
arr5[[0, -1]] = 1
arr5[:, [0, -1]] = 1
print(arr5)

# 6.每一行都是0,4的5*5矩阵

arr6 = np.arange(5).reshape(1, 5)
print(arr6.repeat(5, axis=0))

# 7.0,1之间长度为12等差数列

arr7 = np.linspace(0, 1, num=12)
print(arr7)

# 8.长度为10随机数组并排序

arr8 = np.random.randint(1, 100, size=10)
print(arr8)
arr8.sort()
print(arr8)

# 9.创建符合类型

student = np.dtype(
    [('name', '<U20'), ('id', 'i4'), ('age', 'i1')]
)

arr9 = np.array([('tom', 1, 18), ('lily', 2, 22)], dtype=student)

print(arr9)