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Convert a python dict to a string and back
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@TylerEaves Can you provide example how it should be done.
– Boban
Sep 11 '16 at 9:43
1
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Efficient SQL test query or validation query that will work across all (or most) databases
... for idleness. For example, the JDBC pooling library c3p0 has a property called preferredTestQuery , which gets executed on the connection at configured intervals. Similarly, Apache Commons DBCP has validationQuery .
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How would you do a “not in” query with LINQ?
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where !(from o in dc.Orders
select o.CustomerID)
.Contains(c.CustomerID)
select c;
foreach (var c in query) Console.WriteLine( c );
from The NOT IN clause in LINQ to SQL by Marco Russo
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When to call activity context OR application context?
... Context from getApplicationContext() holds onto something created by your calls on it that you don't clean up. With an Activity, if it holds onto something, once the Activity gets garbage collected, everything else flushes out too. The Application object remains for the lifetime of your process.
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Do you use NULL or 0 (zero) for pointers in C++?
...ided. That's less common these days.
If you have to name the null pointer, call it nullptr; that's what it's called in C++11. Then, nullptr will be a keyword.
That said, don't sweat the small stuff.
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Is it possible to await an event instead of another async method?
...r the statement to run as a continuation on the Task or awaitable that you call await on. More often than not, it is some sort of asynchronous operation, which could be IO completion, or something that is on another thread.
– casperOne
Oct 12 '12 at 13:26
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Rake just one migration
...and on what Ryan says, if the table has been dropped from the database outside of Rails, rake db:migrate:up VERSION=my_version may do nothing, because the schema_migrations table still says it is has been run. In the same situation rake db:migrate:redo VERSION=my_version may fail because it cannot d...
What's the difference between a Future and a Promise?
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According to this discussion, Promise has finally been called CompletableFuture for inclusion in Java 8, and its javadoc explains:
A Future that may be explicitly completed (setting its value and status), and may be used as a CompletionStage, supporting dependent functions an...
理解Python的 with 语句 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...ows with is evaluated, the __enter__() function on the resulting object is called. The value returned by this function is assigned to the variable following as. After every statement in the block is evaluated, the __exit__() function is called.
紧跟with后面的语句被求值后，返回对象...
What is the difference between string primitives and String objects in JavaScript?
...erms of functionality. That aside, the behaviour you are trying to name is called auto-boxing. So what actually happens is that a primitive is converted to its wrapper type when a method of the wrapper type is invoked. Put simple:
var s = 'test';
Is a primitive data type. It has no methods, it is...