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When is it better to use an NSSet over an NSArray?
... is that a set uses hash values to find items (like a dictionary) while an array has to iterate over its entire contents to find a particular object.
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Declare a const array
...t can only be applied to a field whose value is known at compile-time. The array initializer you've shown is not a constant expression in C#, so it produces a compiler error.
Declaring it readonly solves that problem because the value is not initialized until run-time (although it's guaranteed to h...
Postgresql GROUP_CONCAT equivalent?
...s is probably a good starting point (version 8.4+ only):
SELECT id_field, array_agg(value_field1), array_agg(value_field2)
FROM data_table
GROUP BY id_field
array_agg returns an array, but you can CAST that to text and edit as needed (see clarifications, below).
Prior to version 8.4, you have to...
Arrays vs Vectors: Introductory Similarities and Differences [closed]
What are the differences between an array and a vector in C++? An example of the differences might be included libraries, symbolism, abilities, etc.
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Convert NSArray to NSString in Objective-C
I am wondering how to convert an NSArray [@"Apple", @"Pear ", 323, @"Orange"] to a string in Objective-C .
9 Answers
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Most efficient way to prepend a value to an array
Assuming I have an array that has a size of N (where N > 0 ), is there a more efficient way of prepending to the array that would not require O(N + 1) steps?
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Checking for empty arrays: count vs empty
This question on ' How to tell if a PHP array is empty ' had me thinking of this question
12 Answers
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Multiple returns from a function
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There is no way of returning 2 variables. Although, you can propagate an array and return it; create a conditional to return a dynamic variable, etc.
For instance, this function would return $var2
function wtf($blahblah = true) {
$var1 = "ONe";
$var2 = "tWo";
if($blahblah === true) ...
Are negative array indexes allowed in C?
... you don't have to dereference the pointer to get UB. Merely computing somearray-2 is undefined unless the result is in the range from the start of somearray to 1 past its end.
– RBerteig
Aug 13 '10 at 9:12
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What is the best way to convert an array to a hash in Ruby
In Ruby, given an array in one of the following forms...
11 Answers
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