python zeros用法实例

　　编程就是踩坑的过程。今天又踩了一个坑，做个积累吧。

在给数组赋初始值的时候，经常会用到0数组，而Python中，我们使用zero（）函数来实现。在默认的情况下，zeros创建的数组元素类型是浮点型的，如果要使用其他类型，可以设置dtype参数进行声明。下面通过一个例子来说明：

　　１默认参数的例子：

　　

import numpy as np

r = 10
c = 10

D0 = np.zeros((11,11))
#D0 = np.zeros((11,11),dtype=int)

D0[0, 1:] = 32767
D0[1:, 0] = 32767

for i in range(r):
        for j in range(c):
            D0[i + 1, j + 1] = 1
print D0
~                  

　　运行结果：

[[  0.00000000e+00   3.27670000e+04   3.27670000e+04   3.27670000e+04
    3.27670000e+04   3.27670000e+04   3.27670000e+04   3.27670000e+04
    3.27670000e+04   3.27670000e+04   3.27670000e+04]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]
 [  3.27670000e+04   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00   1.00000000e+00
    1.00000000e+00   1.00000000e+00   1.00000000e+00]]

　　２　参数为整形的例子：

 import numpy as np

 r = 10
 c = 10

 #D0 = np.zeros((11,11))
 D0 = np.zeros((11,11),dtype=int)

 D0[0, 1:] = 32767
 D0[1:, 0] = 32767

 for i in range(r):
         for j in range(c):
             D0[i + 1, j + 1] = 1
 print D0

　　运行结果：

[[    0 32767 32767 32767 32767 32767 32767 32767 32767 32767 32767]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]
 [32767     1     1     1     1     1     1     1     1     1     1]]

　　可以看出，该zeros默认的是float类型，要使用别的类型需要加符号的，我就是在这个上面躺枪了。