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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...
JSON.parse vs. eval()
...n.parse just parses JSON whereas eval would leave the door open to all JS expressions.
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How to truncate string using SQL server
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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 ...
Parse JSON in C#
I'm trying to parse some JSON data from the Google AJAX Search API. I have this URL and I'd like to break it down so that the results are displayed. I've currently written this code, but I'm pretty lost in regards of what to do next, although there are a number of examples out there with simplifie...
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
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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]]
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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.
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CSS: fixed position on x-axis but not y?
Is there a way to fix a position on the x-axis only? So when a user scrolls up, the div tag will scroll up with it, but not side to side?
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