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Why does writeObject throw java.io.NotSerializableException and how do I fix it?
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3 Answers
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Do declared properties require a corresponding instance variable?
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93
If you are using the Modern Objective-C Runtime (that's either iOS 3.x or greater, or 64-bit Sno...
Incomplete type is not allowed: stringstream
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XML schema or DTD for logback.xml?
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It is not supported officially according to the documentation, but there is an independent proj...
What is the Invariant Culture?
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The invariant culture is a special culture which is useful because it will not change. The curr...
How to implement __iter__(self) for a container object (Python)
...n some_list.
def __iter__(self):
yield 5
yield from some_list
Pre-3.3, yield from didn't exist, so you would have to do:
def __iter__(self):
yield 5
for x in some_list:
yield x
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How to sort a dataframe by multiple column(s)
... code:
R> dd[with(dd, order(-z, b)), ]
b x y z
4 Low C 9 2
2 Med D 3 1
1 Hi A 8 1
3 Hi A 9 1
Edit some 2+ years later: It was just asked how to do this by column index. The answer is to simply pass the desired sorting column(s) to the order() function:
R> dd[order(-dd[,4], dd[,1]), ...