NumPy(Numerical Python)是Python语言的一个扩展程序库，支持大量的维度数组与矩阵运算，此外也针对数组运算提供大量的数学函数库。

NumPy的前身Numeric最早是由Jim Hugunin与其它协作者共同开发，2005 年，Travis Oliphant在Numeric中结合了另一个同性质的程序库Numarray的特色，并加入了其它扩展而开发了NumPy。NumPy为开放源代码并且由许多协作者共同维护开发。

# coding=utf-8
import numpy as np#使用numpy生成数组,得到ndarray的类型
t1 = np.array([1,2,3,])
print(t1)
print(type(t1))t2 = np.array(range(10))
print(t2)
print(type(t2))t3 = np.arange(4,10,2)
print(t3)
print(type(t3))
print(t3.dtype)

# coding=utf-8
import numpy as np
import random# int8, int16, int32, int64 四种数据类型可以使用字符串 'i1', 'i2','i4','i8' 代替
t1 = np.array(range(1,4),dtype="i1")
print(t1)
print(t1.dtype)##numpy中的bool类型
t2 = np.array([1,1,0,1,0,0],dtype=bool)
print(t2)
print(t2.dtype)#调整数据类型
t3 = t2.astype("int8")
print(t3)
print(t3.dtype)#numpy中的小数
t4 = np.array([random.random() for i in range(10)])
print(t4)
print(t4.dtype)t5 = np.round(t4,2)
print(t5)

# coding=utf-8
import numpy as npa = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])
print(a)#查看数组形状
print(a.shape)#修改数组形状
print(a.reshape(3,4))#原数组形状不变
print(a.shape)b = a.reshape(3,4)print(b.shape)print(b)#把数组转化为1维度数据
print(b.reshape(1,12))print(b.flatten())

# coding=utf-8
import numpy as npa = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])print(a)#加法减法
print(a+5)
print(a-5)#乘法除法
print(a*3)
print(a/3)

# coding=utf-8
import numpy as npa = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])b = np.array([[21,22,23,24,25,26],[27,28,29,30,31,32]])#数组和数组的加减法
print(a+b)
print(a-b)#数组和数组的乘除法
print(a*b)
print(a/b)

# coding=utf-8
import numpy as npa = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])c = np.array([[1,2,3,4],[5,6,7,8],[9,10,11,12]])#不同维度的数组计算
print(a*c)

# coding=utf-8
import numpy as np
#2行6列的数组
a = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])
#1行6列的数组
c = np.array([1,2,3,4,5,6])print(a-c)
print(a*c)

# coding=utf-8
import numpy as np
#2行6列的数组
a = np.array([[3,4,5,6,7,8],[4,5,6,7,8,9]])
#1行6列的数组
c = np.array([[1],[2]])print(a+c)
print(a*c)
print(c*a)