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LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria
...amount of results but you state that you only want the first one.
I personally find the semantics very different and using the appropriate one, depending on the expected results, improves readability.
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How are software license keys generated?
... honest, this strikes me as (in)Security Through Obscurity , although I really have no idea how license keys are generated. What is a good (secure) example of license key generation? What cryptographic primitive (if any) are they using? Is it a message digest? If so, what data would they be hashing...
Access Container View Controller from Parent iOS
...troller is made a child of the first view controller. prepareForSegue: is called just before this happens. you can use this opportunity to pass data to the child, or to store a reference to the child for later use. see also developer.apple.com/library/ios/#documentation/uikit/reference/…
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CSS: center element within a element
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is there a way to make this center the element vertically as well as horizontally?
– Gman Smith
Jan 17 '16 at 19:01
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Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug
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This is going to sound stupid, but I tried all these solutions, running VS2010 on Windows 7. None of them worked except the renaming and building, which was VERY tedious to say the least. Eventually, I tracked down the culprit, and I find it hard to believe. But I was...
How to run cron once, daily at 10pm
...'s date, it happened to me to set crontab to start a job at 22, but it actually started at 23 because the system was UTC (so 22 for the system was 23 for me in GMT).
– nnsense
Apr 24 '19 at 18:10
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Iterating over every two elements in a list
... y in pairwise(l):
print "%d + %d = %d" % (x, y, x + y)
Or, more generally:
from itertools import izip
def grouped(iterable, n):
"s -> (s0,s1,s2,...sn-1), (sn,sn+1,sn+2,...s2n-1), (s2n,s2n+1,s2n+2,...s3n-1), ..."
return izip(*[iter(iterable)]*n)
for x, y in grouped(l, 2):
print...
Why do we use arrays instead of other data structures?
...des O(1) access time.
MyArray [5]
^ ^
Pointer Offset
All other data structures either build upon this, or do not use adjacent memory for storage, resulting in poor random access look up time (Though there are other benefits to not using sequential memory).
For example, let's s...
Why does the C# compiler go mad on this nested LINQ query?
...o compile following code and you'll find that compiler takes >3 GB of RAM (all free memory on my machine) and very long time to compile (actually I get IO exception after 10 minutes).
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Python idiom to return first item or None
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Oh, I don't like this at all. If any item in the list evaluates False, that value is discarded and replaced. If you have an empty string "" in the list, that is discarded and replaced by an empty list []. If you have a 0, also replaced by []. If ...