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How to define a two-dimensional array?
...tems; Python calls this
"list comprehension".
# Creates a list containing 5 lists, each of 8 items, all set to 0
w, h = 8, 5;
Matrix = [[0 for x in range(w)] for y in range(h)]
You can now add items to the list:
Matrix[0][0] = 1
Matrix[6][0] = 3 # error! range...
Matrix[0][6] = 3 # valid
Not...
LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...题：
在模型窗口中输入如下代码：
min=2*x1+3*x2;
x1+x2>=350;
x1>=100;
2*x1+x2<=600;
然后点击工具条上的按钮 即可。
例1.2 使用LINGO软件计算6个发点8个收点的最小费用运输问题。产销单位运价如下表。
销地
产地
...
How to get Top 5 records in SqLite?
...
586
SELECT * FROM Table_Name LIMIT 5;
...
How to convert list of tuples to multiple lists?
...n zip() will almost do what you want:
>>> zip(*[(1, 2), (3, 4), (5, 6)])
[(1, 3, 5), (2, 4, 6)]
The only difference is that you get tuples instead of lists. You can convert them to lists using
map(list, zip(*[(1, 2), (3, 4), (5, 6)]))
...
Returning first x items from array
I want to return first 5 items from array. How can I do this?
5 Answers
5
...
php动态安装mysql扩展错误（ext/mysqlnd/mysqlnd.h: No such file or direc...
...rectory）错误如下：In file included from data xingzheng install php-5.5.10 include php Zend zend_compile.h:719, from ...错误如下：
In file included from /data/xingzheng/install/php-5.5.10/include/php/Zend/zend_compile.h:719,
from /data/xingzheng/install/php...
Logical operators for boolean indexing in Pandas
...
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How do I interpret precision and scale of a number in a database?
I have the following column specified in a database: decimal(5,2)
3 Answers
3
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Is it better to use std::memcpy() or std::copy() in terms to performance?
...ner was std::copy.
I wrote a C++ SHA-2 implementation. In my test, I hash 5 strings using all four SHA-2 versions (224, 256, 384, 512), and I loop 300 times. I measure times using Boost.timer. That 300 loop counter is enough to completely stabilize my results. I ran the test 5 times each, alternati...