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Fastest check if row exists in PostgreSQL
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How about simply:
select 1 from tbl where userid = 123 limit 1;
where 123 is the userid of the batch that you're about to insert.
The above query will return either an empty set or a single row, depending on whether there are records with the given userid.
If this turns o...
What is boxing and unboxing and what are the trade offs?
...xing is the conversion of a reference type into a value type.
EX: int i = 123;
object o = i;// Boxing
int j = (int)o;// UnBoxing
Value Types are: int, char and structures, enumerations.
Reference Types are:
Classes,interfaces,arrays,strings and objects
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Grep characters before and after match?
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3 characters before and 4 characters after
$> echo "some123_string_and_another" | grep -o -P '.{0,3}string.{0,4}'
23_string_and
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How do I fetch a single model in Backbone?
...ers with the hashbang in your URL like so, http://www.mydomain.com/#clocks/123 , but it should work even if you haven't yet.
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...red Jul 15 '13 at 22:16
Thejoker123Thejoker123
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Python equivalent of D3.js
...wered Oct 10 '13 at 19:28
sk8asd123sk8asd123
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Array initialization syntax when not in a declaration
...answered Mar 25 '16 at 4:04
user123user123
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cout保留两位小数输出 - C/C++ - 清泛网 - 专注C/C++及内核技术
...precision函数需要引入该头文件
int main() {
double dval = 123.456789;
// C风格
printf("in C: %.2f\n", dval);
// cout固定输出几位（整数+小数一起）
std::cout << std::setprecision(5) << dval << std::endl;
// cout固定输出2位小数，整数...
App Inventor 2 Clipboard 拓展：实现剪贴板的复制粘贴功能 · App Inventor 2 中文网
...基于 TaifunClipboard 拓展 开发。
.aix 拓展下载：
cn.fun123.Clipboard.aix
demo程序下载：
Clipboard.aia
使用方法
属性及方法很简单，默认操作成功后显示提示信息，SuppressToast设置为 假 后，则不显示提示信息。
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Checking if object is empty, works with ng-show but not from controller?
...wered May 8 '14 at 22:21
testing123testing123
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