大约有 13,922 项符合查询结果（耗时：0.0235秒） [XML]
二维码的生成细节及原理 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...下二维码一共有40个尺寸。官方叫版本Version。Version 1是21 x 21的矩阵，Version 2是 25 x 25的矩阵，Version 3是29的尺寸，每增加一个version，就会增加4的尺寸，公式是：(V-1)*4 + 21（V是版本号） 最高Version 40，(40-1)*4+21 = 177，所以最高是177...
How can I reliably determine the type of a variable that is declared using var at design time?
...ween keystrokes.
When the IDE needs to work out the type of a particular expression inside a method body -- say you've typed "foo." and we need to figure out what are the members of foo -- we do the same thing; we skip as much work as we reasonably can.
We start with a pass which analyzes only th...
How to upgrade PowerShell version from 2.0 to 3.0
...wnload and install from http://www.microsoft.com/en-us/download/details.aspx?id=34595. You need Windows 7 SP1 though.
It's worth keeping in mind that PowerShell 3 on Windows 7 does not have all the cmdlets as PowerShell 3 on Windows 8. So you may still encounter cmdlets that are not present on you...
Getting the exception value in Python
...
use str
try:
some_method()
except Exception as e:
s = str(e)
Also, most exception classes will have an args attribute. Often, args[0] will be an error message.
It should be noted that just using str will return an empty string if there's no error...
How do I compare two hashes?
...ws deep comparison of hashes and arrays in the hash.
The following is an example:
a = {a:{x:2, y:3, z:4}, b:{x:3, z:45}}
b = {a:{y:3}, b:{y:3, z:30}}
diff = HashDiff.diff(a, b)
diff.should == [['-', 'a.x', 2], ['-', 'a.z', 4], ['-', 'b.x', 3], ['~', 'b.z', 45, 30], ['+', 'b.y', 3]]
...
JSON.parse vs. eval()
...n.parse just parses JSON whereas eval would leave the door open to all JS expressions.
share
|
improve this answer
|
follow
|
...
How to terminate the script in JavaScript?
How can I exit the JavaScript script much like PHP's exit or die ? I know it's not the best programming practice but I need to.
...
What is a wrapper class?
...raction from the implementation of the underlying class or component; for example, wrapper classes that wrap COM components can manage the process of invoking the COM component without bothering the calling code with it. They can also simplify the use of the underlying object by reducing the number...
How to truncate string using SQL server
...
If col is exactly 15 in length it will get the entire string when doing left(col,15) and then put '...' on the end. Surely a better solution is checking 'when len(col) > 15'.
– Murphybro2
Dec 6 ...