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Difference between Covariance & Contra-variance
...ng function that associates one member of a set with another. More specifically, a mapping can be covariant or contravariant with respect to a relation on that set.
Consider the following two subsets of the set of all C# types. First:
{ Animal,
Tiger,
Fruit,
Banana }.
And second, this c...
Objective-C formatting string for boolean?
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I love cake and no cake! I am going to replace all my x?@"YES":@"NO" code with x?@"Cake":@"No Cake" immediately :D -- well, at least for my object descriptions anyway ;)
– Jason Coco
Apr 8 '10 at 23:26
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Is a Java hashmap search really O(1)?
...say, balanced trees, its behavior is probabilistic. In these cases its usually most helpful to talk about complexity in terms of the probability of a worst-case event occurring would be. For a hash map, that of course is the case of a collision with respect to how full the map happens to be. A co...
Why does sizeof(x++) not increment x?
..., in particular this would mean that in something like sizeof(int[++x]) (really, really a bad idea, anyhow) the ++ could be evaluated.
– Jens Gustedt
Nov 22 '11 at 12:01
3
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What programming practice that you once liked have you since changed your mind about? [closed]
As we program, we all develop practices and patterns that we use and rely on. However, over time, as our understanding, maturity, and even technology usage changes, we come to realize that some practices that we once thought were great are not (or no longer apply).
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Format numbers to strings in Python
...}.html'.format(**d)
'http://xxx.yyy.zzz/user/42.html'
Like Python 2.6+, all Python 3 releases (so far) understand how to do both. I shamelessly ripped this stuff straight out of my hardcore Python intro book and the slides for the Intro+Intermediate Python courses I offer from time-to-time. :-)
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is it possible to evenly distribute buttons across the width of an android linearlayout
I have a linear layout (oriented horizontally) that contains 3 buttons. I want the 3 buttons to have a fixed width and be evenly distributed across the width of the linear layout.
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Running PostgreSQL in memory only
I want to run a small PostgreSQL database which runs in memory only, for each unit test I write. For instance:
8 Answers
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Check if bash variable equals 0 [duplicate]
...and appears empty to bash. You can verify this using the below tests which all evaluate to true because xyz is either empty or unset:
if [ -z ] ; then echo "true"; else echo "false"; fi
xyz=""; if [ -z "$xyz" ] ; then echo "true"; else echo "false"; fi
unset xyz; if [ -z "$xyz" ] ; then echo "t...
The Android emulator is not starting, showing “invalid command-line parameter”
...th R12 where the SDK location cannot contain any spaces.
The default installation location is: C:\Programme Files(x86)\Android\android-sdk. They are currently fixing the problem but you can currently work around it by changing the SDK location path in eclipse to C:\PROGRA~2\Android\android-sdk.
I...