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ETag vs Header Expires
...d around but haven't been able to figure out if I should use both an ETag and an Expires Header or one or the other.
8 ...
Understanding REST: Verbs, error codes, and authentication
... APIs around default functions in my PHP-based web applications, databases and CMSs.
10 Answers
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How to fix “Headers already sent” error in PHP
...ically
Previous error messages or notices
Intentional:
print, echo and other functions producing output
Raw <html> sections prior <?php code.
Why does it happen?
To understand why headers must be sent before output it's necessary
to look at a typical HTTP
response. PHP scripts ...
Is it safe to check floating point values for equality to 0?
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It is safe to expect that the comparison will return true if and only if the double variable has a value of exactly 0.0 (which in your original code snippet is, of course, the case). This is consistent with the semantics of the == operator. a == b means "a is equal to b".
It is not sa...
What are the rules about using an underscore in a C++ identifier?
...e allowed to add template specializations, though.)
From the 2003 C++ Standard:
17.4.3.1.2 Global names [lib.global.names]
Certain sets of names and function signatures are always reserved to the implementation:
Each name that contains a double underscore (__) or begins with an u...
javax.faces.application.ViewExpiredException: View could not be restored
... application with container-managed security. The problem is when I log in and open another page on which I logout, then I come back to first page and I click on any link etc or refresh page I get this exception. I guess it's normal (or maybe not:)) because I logged out and session is destroyed. Wha...
What is the difference between Left, Right, Outer and Inner Joins?
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Simple Example: Lets say you have a Students table, and a Lockers table. In SQL, the first table you specify in a join, Students, is the LEFT table, and the second one, Lockers, is the RIGHT table.
Each student can be assigned to a locker, so there is a LockerNumber column in...
How do I check if a column is empty or null in MySQL?
...e_col = ' ' (one space inserted in the string) then it works on both MySQL and Oracle, see answer of "onedaywhen". some_col = '' doesn't work on Oracle as empty strings mean NULL there.
– Johanna
May 18 '15 at 14:07
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What is “entropy and information gain”?
I am reading this book ( NLTK ) and it is confusing. Entropy is defined as :
7 Answers
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What does ||= (or-equals) mean in Ruby?
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This question has been discussed so often on the Ruby mailing-lists and Ruby blogs that there are now even threads on the Ruby mailing-list whose only purpose is to collect links to all the other threads on the Ruby mailing-list that discuss this issue.
Here's one: The definitive list of ||= ...