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PostgreSQL: Difference between text and varchar (character varying)
...s are needed to check the length, if one is given, and the extra space and time required if padding is needed for char(n).
However, when you only need to store a single character, there is a slight performance advantage to using the special type "char" (keep the double-quotes — they're part of th...
Difference between Covariance & Contra-variance
...ject> to Action<string>; values only go into these objects.
This time it works because if the API is expecting something general (like object) you can give it something more specific (like string).
More generally
If you have an interface IFoo<T> it can be covariant in T (i.e. decla...
How do you create a dictionary in Java? [closed]
... way, you actually don't need to include <String, String> the second time. You can just do Map<String, String> map = new HashMap<>();
– Samuel Noyes
Apr 6 '16 at 15:12
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How to check whether a string is a valid HTTP URL?
There are the Uri.IsWellFormedUriString and Uri.TryCreate methods, but they seem to return true for file paths etc.
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Which cryptographic hash function should I choose?
... one wins the intergalactic lottery, ever.
But ... MD5 is broken
Sometimes the fact that its broken does not matter.
As it stands there are no known pre-image or second pre-image attacks on MD5.
So what is so broken about MD5, you may ask? It is possible for a third party to generate 2 mess...
How to check if a file is a valid image file?
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A lot of times the first couple chars will be a magic number for various file formats. You could check for this in addition to your exception checking above.
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How to get HTTP Response Code using Selenium WebDriver
...s/wws/webpage1.html","initiator":{"type":"other"},"loaderId":"3928.1","wallTime":1.47619492749007E9,"type":"Document","timestamp":20226.652971}}}
{"webview":"3b8eaedb-bd0f-4baa-938d-4aee4039abfe","message":{"method":"Network.responseReceived","params":{"frameId":"3928.1","requestId":"3928.1","re...
How to output only captured groups with sed?
Is there any way to tell sed to output only captured groups? For example given the input:
8 Answers
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What's the most efficient way to erase duplicates and sort a vector?
I need to take a C++ vector with potentially a lot of elements, erase duplicates, and sort it.
23 Answers
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NHibernate vs LINQ to SQL
...tructure. For simple applications, this is perfectly acceptable (and oftentimes even preferable), but for more complex applications devs will often suggest using a domain driven design pattern instead (which is what NHibernate facilitates).
The problem with the table-per-class pattern is that your...