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In SQL, what's the difference between count(column) and count(*)?
... are often left blank, like the user's Website URL.
-- count(column_name) vs. count(*)
-- Illustrates the difference between counting a column
-- that can hold null values, a 'not null' column, and count(*)
select count(WebsiteUrl), count(Id), count(*) from Users
If you run the query above in ...
How to change Navigation Bar color in iOS 7?
...nController.navigationBar respondsToSelector:@selector(setBarTintColor:)]) vs the version number to check if you can set the barTintColor
– SimpsOff
Dec 24 '13 at 17:32
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Why and How to avoid Event Handler memory leaks?
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Jon SkeetJon Skeet
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Check that an email address is valid on iOS [duplicate]
... return [emailTest evaluateWithObject:checkString];
}
Discussion on Lax vs. Strict - http://blog.logichigh.com/2010/09/02/validating-an-e-mail-address/
And because categories are just better, you could also add an interface:
@interface NSString (emailValidation)
- (BOOL)isValidEmail;
@end
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Format a datetime into a string with milliseconds
...str(datetime.datetime.utcnow()) being called in each iteration of the test vs setting it once?
– Austin Marshall
Sep 28 '11 at 22:10
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How can I programmatically determine if my app is running in the iphone simulator?
...ounts for x86_64 and i386 architectures. Helped me overcome a weird device vs. simulator bug in Core Data. You're the man!
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Is Disney's FastPass Valid and/or Useful Queue Theory
...rity.
– brian d foy
Mar 17 '09 at 8:27
The concept assumes it because the implementation enforces it. We're discussing...
Why do we use volatile keyword? [duplicate]
...read. (c) MSDN C++ Reference. (msdn.microsoft.com/en-us/library/12a04hfd(v=vs.80).aspx) But certainly msdn and wikipedia are wrong, and you are correct.
– Ivan
Dec 14 '10 at 10:54
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Adding div element to body or document in JavaScript
...tach it to the DOM. Check this comparision on jsperf: jsperf.com/innerhtml-vs-appendchild2
– fegemo
Feb 11 '15 at 12:54
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LINQ: Select an object and change some properties without creating a new object
...SomeProp = "foo"; return x; })
What this does is use an anonymous method vs and expression. This allows you to use several statements in one lambda. So you can combine the two operations of setting the property and returning the object into this somewhat succinct method.
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