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Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL?
...an work around it from within psql by executing the DDL statement conditionally:
SELECT 'CREATE DATABASE mydb'
WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'mydb')\gexec
The manual:
\gexec
Sends the current query buffer to the server, then treats each column of each row of the query's...
Which rows are returned when using LIMIT with OFFSET in MySQL?
...data between the two digits but now its clear :)
– MR_AMDEV
Sep 16 '18 at 15:09
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remove None value from a list without removing the 0 value
... - it's just for scientific purposes)
>>> from operator import is_not
>>> from functools import partial
>>> L = [0, 23, 234, 89, None, 0, 35, 9]
>>> filter(partial(is_not, None), L)
[0, 23, 234, 89, 0, 35, 9]
...
[精华]VC++对话框程序打印及打印预览的实现 - C/C++ - 清泛网 - 专注C/C++及内核技术
...程序文件菜单中会生成两个菜单项分别是打印（标识符ID_FILE_PRINT）和打印预览(标识符：ID_FILE_PRINT_PREVIEW)，展开程序源代码，可以发现，是CVIEW类提供标准打印和打印预览菜单命令的消息处理函数：
设应用程序视图类为CMyView,展...
Environment variable to control java.io.tmpdir?
...s.
On Windows, OpenJDK's get_temp_directory() function makes a Win32 API call to GetTempPath(); this is how on Windows, Java reflects the value of the TMP environment variable.
On Linux and Solaris, the same get_temp_directory() functions return a static value of /tmp/.
I don't know if the actual...
How to open a new tab using Selenium WebDriver?
...ow. Obviously, you'd need to keep track of the window name(s) as normal to allow switching between them.
– Mark Rowlands
Jul 16 '13 at 15:42
1
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How to sort a list in Scala by two fields?
... @SachinK: You could implement customOrdering as Ordering[Row] manually or using Ordering.by like this: val customOrdering = Ordering.by((r: Row) => (r.lastName, r.firstName))( Ordering.Tuple2(Ordering.String.reverse, Ordering.String) )`
– senia
Jun ...
Exclude a directory from git diff
...t diff previous_release current_release !(spec)
Saves you having to list all other things.
Or, shell-agnostic:
git diff previous_release current_release --name-only | grep -v '^spec/' \
| xargs git diff previous_release current_release --
You could wrap that up in a one-liner shell script ...
What do the python file extensions, .pyc .pyd .pyo stand for?
...
.py: This is normally the input source code that you've written.
.pyc: This is the compiled bytecode. If you import a module, python will build a *.pyc file that contains the bytecode to make importing it again later easier (and faster).
.pyo...
AngularJS and its use of Dollar Variables
...="n = { visible: 'foo', $ignore: 'bar' };">{{ n }}</div>
Additionally when adding an explicit watcher on a scope object, changes to properties with a leading dollar sign of this object will not trigger the watcher. See this updated fiddle.
angular.equals() ignores keys prefixed with $.
...