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How to output only captured groups with sed?
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answered May 6 '10 at 2:39
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How can I convert a DateTime to the number of seconds since 1970?
...ateTime variable to Unix time, ie, the number of seconds since Jan 1st, 1970. It looks like a DateTime is actually implemented as the number of 'ticks' since Jan 1st, 0001.
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Elastic Search: how to see the indexed data
...ing on your local machine), open a browser window to:
http://localhost:9200/_plugin/head/
Alternatively, you can just use curl from the command line, eg:
Check the mapping for an index:
curl -XGET 'http://127.0.0.1:9200/my_index/_mapping?pretty=1'
Get some sample docs:
curl -XGET 'http:...
Why does (0 < 5 < 3) return true?
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Order of operations causes (0 < 5 < 3) to be interpreted in javascript as ((0 < 5) < 3) which produces (true < 3) and true is counted as 1, causing it to return true.
This is also why (0 < 5 < 1) returns false, (0 < 5) returns t...
Python 3.x rounding behavior
I was just re-reading What’s New In Python 3.0 and it states:
11 Answers
11
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How to debug Lock wait timeout exceeded on MySQL?
...***
Type: InnoDB
Name:
Status:
=====================================
110514 19:44:14 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 4 seconds
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 9014315, signal count 780...
MongoDB sort排序、index索引教程 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...果。
实例
col 集合中的数据如下：
{ "_id" : ObjectId("56066542ade2f21f36b0313a"), "title" : "PHP 教程", "description" : "PHP 是一种创建动态交互性站点的强有力的服务器端脚本语言。", "by" : "菜鸟教程", "url" : "https://www.tsingfun.com", "tags" : [ "php"...
How to check whether a pandas DataFrame is empty?
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505
You can use the attribute df.empty to check whether it's empty or not:
if df.empty:
print(...
“CASE” statement within “WHERE” clause in SQL Server 2008
...ery which contains "CASE" statement within "WHERE" clause. But SQL Server 2008 is giving some errors while executing it. Can anyone please help me with the correct query? Here is the query:
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What are the main uses of yield(), and how does it differ from join() and interrupt()?
...nd Java 6.
In Java 5, Thread.yield() calls the Windows API call Sleep(0). This
has the special effect of clearing the current thread's quantum and
putting it to the end of the queue for its priority level. In other
words, all runnable threads of the same priority (and those of greater
p...