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Most efficient method to groupby on an array of objects
...ailed to understand how in the world does it work starting from ...result. Now I can't sleep because of that.
– user3307073
Mar 29 '19 at 9:26
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How to use gitignore command in git
...nch on github and it pushed all the library and documents into the github. Now what can I do and how can I use gitignore command to avoid the same mistake again.
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/etc/apt/sources.list" E212: Can't open file for writing
...udo vim FILE. Or if you don't want to leave your existing vim session (and now have proper sudo rights), you can issue:
:w !sudo tee % > /dev/null
Which will save the file.
HTH
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Function that creates a timestamp in c#
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//Find unix timestamp (seconds since 01/01/1970)
long ticks = DateTime.UtcNow.Ticks - DateTime.Parse("01/01/1970 00:00:00").Ticks;
ticks /= 10000000; //Convert windows ticks to seconds
timestamp = ticks.ToString();
Adjusting the denominator allows you to choose your level of precision
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SQL multiple column ordering
...en performs STABLE sorting by column1. This is more clear for people that knows what stable sorting is.
– Atom
Oct 3 '16 at 13:49
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How does Windows 8 Runtime (WinRT / Windows Store apps / Windows 10 Universal App) compare to Silver
...nd the new Windows 8 Runtime that is used to create Metro style apps. I know you can use it with XAML and it is based on .NET so C# and VB.NET can be used to write the apps, but then it seems to have something to do with HTML, CSS, DOM, and JavaScript.
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Format LocalDateTime with Timezone in Java8
...= DateTimeFormatter.ofPattern("yyyyMMdd HH:mm:ss.SSSSSS Z");
ZonedDateTime.now().format(FORMATTER);
=> "20140829 14:12:22.122000 +09"
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Is it a good idea to index datetime field in mysql?
...it in conditions frequently in queries. If your only condition is BETWEEN NOW() AND DATE_ADD(NOW(), INTERVAL 30 DAY) and you have no other index in the condition, MySQL will have to do a full table scan on every query. I'm not sure how many rows are generated in 30 days, but as long as it's less t...
How to check status of PostgreSQL server Mac OS X
...o get them to take effect, remember to source it like so:
$ . ~/.bashrc
Now, try it and you should get something like this:
$ show-pg-status
pg_ctl: server is running (PID: 11030)
/usr/local/Cellar/postgresql/9.2.4/bin/postgres
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What does iterator->second mean?
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I'm sure you know that a std::vector<X> stores a whole bunch of X objects, right? But if you have a std::map<X, Y>, what it actually stores is a whole bunch of std::pair<const X, Y>s. That's exactly what a map is - it pai...