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Insert, on duplicate update in PostgreSQL?
...mn_2)
VALUES (1, 'A', 'X'), (2, 'B', 'Y'), (3, 'C', 'Z')
ON CONFLICT (id) DO UPDATE
SET column_1 = excluded.column_1,
column_2 = excluded.column_2;
Searching postgresql's email group archives for "upsert" leads to finding an example of doing what you possibly want to do, in the manual...
What's the best way to do a backwards loop in C/C#/C++?
...y a bit obscure, I would say that the most typographically pleasing way of doing this is
for (int i = myArray.Length; i --> 0; )
{
//do something
}
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Linear Regression and group by in R
I want to do a linear regression in R using the lm() function. My data is an annual time series with one field for year (22 years) and another for state (50 states). I want to fit a regression for each state so that at the end I have a vector of lm responses. I can imagine doing for loop for each ...
How do I convert a string to a number in PHP?
...
You don't typically need to do this, since PHP will coerce the type for you in most circumstances. For situations where you do want to explicitly convert the type, cast it:
$num = "3.14";
$int = (int)$num;
$float = (float)$num;
...
How do I make HttpURLConnection use a proxy?
If I do this...
7 Answers
7
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How to deploy correctly when using Composer's develop / production switch?
...Well, the composer.json and composer.lock file should be committed to VCS. Don't omit composer.lock because it contains important information on package-versions that should be used.
When performing a production deploy, you can pass the --no-dev flag to Composer:
composer.phar install --no-dev
T...
Python + Django page redirect
How do I accomplish a simple redirect (e.g. cflocation in ColdFusion, or header(location:http://) for PHP) in Django?
1...
How do I compute derivative using Numpy?
How do I calculate the derivative of a function, for example
8 Answers
8
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TaifunWiFi 拓展：WiFi Manager WiFi管理器扩展 · App Inventor 2 中文网
...WiFi状态检查
// 检查WiFi状态
when Screen1.Initialize
do
if WiFi1.IsEnabled then
set Label1.Text to "WiFi已启用"
set Label2.Text to "当前IP: " & WiFi1.LocalIP
set Label3.Text to "当前SSID: " & WiFi1.SSID
else
set Label1.Text to "WiF...
How to access custom attributes from event object in React?
...render custom attributes as described at
http://facebook.github.io/react/docs/jsx-gotchas.html :
15 Answers
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