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Fastest check if row exists in PostgreSQL
...
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...
Named colors in matplotlib
... can also plot colors by their HTML hex code:
plt.plot([1,2], lw=4, c='#8f9805')
This is more similar to specifying and RGB tuple rather than a named color (apart from the fact that the hex code is passed as a string), and I will not include an image of the 16 million colors you can choose from.....
Insert all values of a table into another table in SQL
...dited Feb 26 '14 at 1:12
hichris123
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answered Apr 21 '10 at 9:35
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How do I properly escape quotes inside HTML attributes?
...gh, try <option value='<?php echo htmlentities("' onmouseover='alert(123);' foo='"); ?>' /> - make sure you use it with ENT_QUOTES, this is safe: <option value='<?php echo htmlentities("' onmouseover='alert(123);' foo='", ENT_QUOTES); ?>' /> , but in addition to ENT_QUOTES y...
Check if element exists in jQuery [duplicate]
...swered Feb 13 '14 at 4:38
Gaurav123Gaurav123
4,18566 gold badges4040 silver badges7070 bronze badges
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Easiest way to compare arrays in C#
...or tuples via using StructuralComparisons type:
object[] a1 = { "string", 123, true };
object[] a2 = { "string", 123, true };
Console.WriteLine (a1 == a2); // False (because arrays is reference types)
Console.WriteLine (a1.Equals (a2)); // False (because arrays is reference types)
IStruct...
App Inventor 2 软件著作权（软著）申请指南 · App Inventor 2 中文网
...验的，建议找人代理一下，细节还是很多很繁琐的。
fun123.cn 提供专业的 AppInventor 源码软著代申请服务，承诺不下证退全款。
5、注意事项
不要有 Logo——有概率会要求提供证明材料，PS掉就行。
不要有其...
App Inventor 2 BLE扩展源码分析 - WriteBytes vs WriteStrings 23字节硬编...
... MTU 值
四、WriteStrings 的问题清单
#问题影响严重程度123字节截断超过23字节的字符串被静默截断，无警告严重2Null终止符默认开启nullTerminateStrings = true，占用1字节，实际可用仅22字节中等3只取 data.get(0)只写第一个字符串，忽...
“Variable” variables in Javascript?
... try using eval():
var data = "testVariable";
eval("var temp_" + data + "=123;");
alert(temp_testVariable);
Or using the window object:
var data = "testVariable";
window["temp_" + data] = 123;
alert(window["temp_" + data]);
http://www.hiteshagrawal.com/javascript/dynamic-variables-in-javascrip...
linux svn搭建配置及svn命令详解 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...asswd
[users]
# harry = harryssecret
# sally = sallyssecret
hello=123
用户名=密码
这样我们就建立了hello用户， 123密码
2.2 再设置权限authz
[root@www ~]# vi authz
[/]
hello= rw
意思是hello用户对所有的目录有读写权限，当然也...