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Create an index on a huge MySQL production table without table locking
...d or dropped. The CREATE INDEX or DROP INDEX statement only finishes after all transactions that are accessing the table are completed, so that the initial state of the index reflects the most recent contents of the table. Previously, modifying the table while an index is being created or dropped ty...
JavaScript Regular Expression Email Validation [duplicate]
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If you define your regular expression as a string then all backslashes need to be escaped, so instead of '\w' you should have '\\w'.
Alternatively, define it as a regular expression:
var pattern = /^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$/;
BTW, please don't validate email address...
AttributeError: 'module' object has no attribute 'urlopen'
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A Python 2+3 compatible solution is:
import sys
if sys.version_info[0] == 3:
from urllib.request import urlopen
else:
# Not Python 3 - today, it is most likely to be Python 2
# But note that this might need an update when Python 4
# might be around one day
from urlli...
浮点数在内存中的表示 - C/C++ - 清泛网 - 专注C/C++及内核技术
浮点数在内存中的表示Float_Memory_Representation一般我们常见的字符型、整型在内存中采用标准的二进制存储,但是程序员往往容易忽略浮点数在内存中的储存方式,从而会导致一些误用,最常见的是浮点数等于零的判断。只有理解...
浮点数在内存中的表示 - C/C++ - 清泛网移动版 - 专注C/C++及内核技术
浮点数在内存中的表示Float_Memory_Representation一般我们常见的字符型、整型在内存中采用标准的二进制存储,但是程序员往往容易忽略浮点数在内存中的储存方式,从而会导致一些误用,最常见的是浮点数等于零的判断。只有理解...
浮点数在内存中的表示 - C/C++ - 清泛网 - 专注C/C++及内核技术
浮点数在内存中的表示Float_Memory_Representation一般我们常见的字符型、整型在内存中采用标准的二进制存储,但是程序员往往容易忽略浮点数在内存中的储存方式,从而会导致一些误用,最常见的是浮点数等于零的判断。只有理解...
Is there a wikipedia API just for retrieve content summary?
...epresents a kind of gamification of the traditional Q&A site or forum. All user-generated content is licensed under a Creative Commons Attribute-ShareAlike license. Questions are closed in order to allow low quality questions to improve. Jeff Atwood stated in 2010 that duplicate questions are no...
Ternary Operator Similar To ?:
...or that we just defined:
object T { val condition = true
import Bool._
// yay!
val x = condition ? "yes" | "no"
}
Have fun ;)
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design a stack such that getMinimum( ) should be O(1)
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EDIT: This fails the "constant space" constraint - it basically doubles the space required. I very much doubt that there's a solution which doesn't do that though, without wrecking the runtime complexity somewhere (e.g. making push/pop O(n)). Note that this doesn't change the complex...
Improve INSERT-per-second performance of SQLite
...more memory will be used for your database.
If you have indices, consider calling CREATE INDEX after doing all your inserts. This is significantly faster than creating the index and then doing your inserts.
You have to be quite careful if you have concurrent access to SQLite, as the whole database i...
