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Sending a message to nil in Objective-C
... anything except keep the compiler happy. Yes, you get the overhead of one more method call, but you save programmer time, which is a far more expensive resource than CPU time. In addition, you're eliminating more code and more conditional complexity from your application.
Clarifying for downvoters...
Regex for numbers only
...ors.
Regex regex = new Regex(@"^\d$");
Use "^\d+$" if you need to match more than one digit.
Note that "\d" will match [0-9] and other digit characters like the Eastern Arabic numerals ٠١٢٣٤٥٦٧٨٩. Use "^[0-9]+$" to restrict matches to just the Arabic numerals 0 - 9.
If you need t...
Pretty git branch graphs
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Update: This answer has gotten far more attention than it deserves. It was originally posted because I think the graphs look nice and they could be drawn-over in Illustrator for a publication– and there was no better solution. But there now exists much...
How to sum a variable by group
...h that "natural-language interpretation" of the tilde operator, it becomes more meaningful (and even intuitive). I personally find this symbolic formula representation better than some of the more verbose alternatives.
– r2evans
Dec 19 '16 at 4:35
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nonlocal keyword in Python 2.x
...ry class and instantiate object instead of the dictionary. I find it much more elegant and readable since it does not flood the code with literals (dictionary keys), plus you can make use of methods.
– Alois Mahdal
Aug 15 '13 at 13:19
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What is the difference between bottom-up and top-down?
...rmination, and thus the bottom of the tree may be infinitely large. Furthermore, in some problems you might not know what the full tree looks like ahead of time. Thus, you might need a strategy/algorithm to decide which subproblems to reveal.)
Memoization, Tabulation
There are at least two main ...
Why is using the JavaScript eval function a bad idea?
...oper use of eval opens up your
code for injection attacks
Debugging can be more challenging
(no line numbers, etc.)
eval'd code executes slower (no opportunity to compile/cache eval'd code)
Edit: As @Jeff Walden points out in comments, #3 is less true today than it was in 2008. However, while some...
Flatten list of lists [duplicate]
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Sorry, I meant more readable/intuitive. Since the OP is having trouble disambiguating between what lists are (sequences of data) and how lists are represented in code (with square brackets), I highly doubt a double list comprehension will m...
How do I concatenate two arrays in C#?
... @manthrax -> In its defense, C# tends to favor lists which are much more powerful than arrays. It seems the only functional purpose for using arrays is for Interop calls (Unmanaged C++).
– Levi Fuller
Oct 26 '15 at 22:40
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How to insert element into arrays at specific position?
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