大约有 40,000 项符合查询结果（耗时：0.0691秒） [XML]
.war vs .ear file
...
Refer: http://www.wellho.net/mouth/754_tar-jar-war-ear-sar-files.html
tar (tape archives)
- Format used is file written in serial units of fileName, fileSize, fileData
- no compression. can be huge
Jar (java archive)
- compression...
Truncating floats in Python
...imal module
str(Decimal(s).quantize(Decimal((0, (1,), -n)), rounding=ROUND_DOWN))
The first step, converting to a string, is quite difficult because there are some pairs of floating point literals (i.e. what you write in the source code) which both produce the same binary representation and yet s...
Bash empty array expansion with `set -u`
...4.4.
$ bash --version | head -n 1
GNU bash, version 4.4.19(1)-release (x86_64-pc-linux-gnu)
$ set -u
$ arr=()
$ echo "foo: '${arr[@]}'"
foo: ''
There is a conditional you can use inline to achieve what you want in older versions: Use ${arr[@]+"${arr[@]}"} instead of "${arr[@]}".
$ function ...
iOS start Background Thread
...ou'd probably be better off using Grand Central Dispatch, though:
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self getResultSetFromDB:docids];
});
GCD is a newer technology, and is more efficient in terms of memory overhead and lines of code.
Updated w...
Memoization in Haskell?
...alling, for example: fix f 123 = 144
We could memoize this by defining:
f_list :: [Int]
f_list = map (f faster_f) [0..]
faster_f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate r...
Force R not to use exponential notation (e.g. e+10)?
...
add a comment
|
158
...
Retrieve only the queried element in an object array in MongoDB collection
...atched shapes element:
db.test.find(
{"shapes.color": "red"},
{_id: 0, shapes: {$elemMatch: {color: "red"}}});
Returns:
{"shapes" : [{"shape": "circle", "color": "red"}]}
In 2.2 you can also do this using the $ projection operator, where the $ in a projection object field name repre...
编程基础与事件状态 05：用过程集中刷新界面 · App Inventor 2 中文网
... 实例名
组件
本课配置
标签_标题
标签
Width=Fill parent；FontSize=24；TextColor=#183153；Text=专注学习 · 第 5课
逐步搭建
找出开始、暂停、Timer 中重复的标签赋值。
建...
Namespace not recognized (even though it is there)
...It would be nice if the error message was better.
– L_7337
Oct 12 '15 at 15:31
|
show 6 more comments
...
How to log PostgreSQL queries?
...o it using a SQL statement like MySQL, but you can send a running server a command to reload the config with pg_ctl reload
– Jarret Hardie
Dec 8 '11 at 8:14
9
...