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Getting the first character of a string with $str[0]
...am just not sure whether this is 'good practice', as that notation is generally used with arrays. This feature doesn't seem to be very well documented so I'm turning to you guys to tell me if it's all right – in all respects – to use this notation?
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What's the cleanest way of applying map() to a dictionary in Swift?
I'd like to map a function on all keys in the dictionary. I was hoping something like the following would work, but filter cannot be applied to dictionary directly. What's the cleanest way of achieving this?
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List of lists changes reflected across sublists unexpectedly
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When you write [x]*3 you get, essentially, the list [x, x, x]. That is, a list with 3 references to the same x. When you then modify this single x it is visible via all three references to it:
x = [1] * 4
l = [x] * 3
print(f"id(x): {id(x)}")
# id(x): 1405608979...
What's the difference between the atomic and nonatomic attributes?
...o are identical; "atomic" is the default behavior (note that it is not actually a keyword; it is specified only by the absence of nonatomic -- atomic was added as a keyword in recent versions of llvm/clang).
Assuming that you are @synthesizing the method implementations, atomic vs. non-atomic chang...
How does collections.defaultdict work?
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Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course th...
How to Load an Assembly to AppDomain with all references recursively?
...e I wrote to solve this problem: github.com/jduv/AppDomainToolkit. Specifically, look at the LoadAssemblyWithReferences method in this class: github.com/jduv/AppDomainToolkit/blob/master/AppDomainToolkit/…
– Jduv
Mar 14 '13 at 14:44
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What is the JavaScript equivalent of var_dump or print_r in PHP? [duplicate]
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This really is not a proper answer as this is not an inherent feature or function of JavaScript and there are innumerable scenarios where one will absolutely not have access to console.log()
– Chris Rasys
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how to stop browser back button using javascript
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There are numerous reasons why disabling the back button will not really work. Your best bet is to warn the user:
window.onbeforeunload = function() { return "Your work will be lost."; };
This page does list a number of ways you could try to disable the back button, but none are guaranteed...
Does Python optimize tail recursion?
...tracebacks:
Tail Recursion Elimination (2009-04-22)
Final Words on Tail Calls (2009-04-27)
You can manually eliminate the recursion with a transformation like this:
>>> def trisum(n, csum):
... while True: # Change recursion to a while loop
... if n == 0:...
How can I create a unique constraint on my column (SQL Server 2008 R2)?
...lready have. It doesn't need to be entered into the expression dialogue at all.
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