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Immutable array in Java
...his can actually come in handy if you are using the List.toArray method to convert a List to an array. Since even an empty array takes up some memory, you can save that memory allocation by creating a constant empty array, and always passing it to the toArray method. That method will allocate a new ...
Find objects between two dates MongoDB
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I just used this to convert my strings to date objects stackoverflow.com/questions/2900674/…
– Tom
May 31 '10 at 21:07
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Checking to see if a DateTime variable has had a value assigned
... null to start with and then assign a normal DateTime value (which will be converted appropriately). Then you can just compare with null (or use the HasValue property) to see whether a "real" value has been set.
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Very large matrices using Python and NumPy
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The HDF library takes care of reading in the relevant chunks of data and converting to NumPy.
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Python 3 turn range to a list
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@jterrace changed "cast" to "convert". You're right about it not being a cast... I don't really know what to call it exactly.
– mgilson
Jul 14 '12 at 1:21
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Select first row in each GROUP BY group?
... Informix 12.x also supports window functions (the CTE needs to be converted to a derived table though). And Firebird 3.0 will also support Window functions
– a_horse_with_no_name
Mar 14 '14 at 9:19
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Correct way to define Python source code encoding
...; :
# This Python file uses the following encoding: utf-8
import os, sys
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Search text in fields in every table of a MySQL database
...NOT
# MISUSE AND YOU COULD CRASH A LARGE SERVER
SELECT
CONCAT('SELECT CONVERT(',A.COLUMN_NAME, ' USING utf8) FROM ', A.TABLE_SCHEMA, '.', A.TABLE_NAME,
' WHERE CONVERT(',A.COLUMN_NAME, ' USING utf8) IN (\'%someText%\');')
FROM INFORMATION_SCHEMA.COLUMNS A
WHERE
A.TABLE...
When to use the brace-enclosed initializer?
...no constructor taking std::initializer_list interfering. Similarly std::is_convertible is of no help.
I've investigated if it is in fact possible to hand-roll a trait that can fix that but I'm not overly optimistic about that. In any case I don't think we would be missing much, I think that the fac...
select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...在1GB内存的机器上大约是10万左右，具体数目可以cat /proc/sys/fs/file-max察看,一般来说这个数目和系统内存关系很大。
总结：
（1）select，poll实现需要自己不断轮询所有fd集合，直到设备就绪，期间可能要睡眠和唤醒多次交替。而...