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python zeros用法实例

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09/25
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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 npr = 10
c = 10D0 = np.zeros((11,11))
#D0 = np.zeros((11,11),dtype=int)D0[0, 1:] = 32767
D0[1:, 0] = 32767for 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。