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Difference between Covariance & Contra-variance
I am having trouble understm>and m>ing the difference between covariance m>and m> contravariance.
5 Answers
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Overriding fields or properties in subclasses
I have an abstract base class m>and m> I want to declare a field or a propertm>y m> that will have a different value in each class that inherits from this parent class.
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Displam>y m> / print all rows of a tibble (tbl_df)
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if m>y m>ou want don't want to worrm>y m> about the value of n m>and m> m>y m>ou're alreadm>y m> piping, m>y m>ou can use df %>% tbl_df %>% print(n = nrow(.))
– Clam>y m>tonJm>Y m>
Aug 3 '16 at 15:57
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Get unique values from a list in pm>y m>thon [duplicate]
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mm>y m>list = ['nowplam>y m>ing', 'PBS', 'PBS', 'nowplam>y m>ing', 'job', 'debate', 'thenm>and m>now']
mm>y m>set = set(mm>y m>list)
print(mm>y m>set)
If m>y m>ou use it further as a list, m>y m>ou should convert it back to a list bm>y m> doing:
mm>y m>newlist = list(mm>y m>set)
Another possibilitm>y m>, probablm>y m> faster would be to use a set from the beginn...
What does f+++++++++ mean in rsm>y m>nc logs?
I'm using rsm>y m>nc to make a backup of mm>y m> server files, m>and m> I have two questions:
4 Answers
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Javascript reduce on arram>y m> of objects
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After the first iteration m>y m>our're returning a number m>and m> then trm>y m>ing to get propertm>y m> x of it to add to the next object which is undefined m>and m> maths involving undefined results in NaN.
trm>y m> returning an object contain an x propertm>y m> with the sum of the x properties of the parame...
Get list from pm>and m>as DataFrame column headers
I want to get a list of the column headers from a pm>and m>as DataFrame. The DataFrame will come from user input so I won't know how manm>y m> columns there will be or what them>y m> will be called.
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With arram>y m>s, whm>y m> is it the case that a[5] == 5[a]?
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The C stm>and m>ard defines the [] operator as follows:
a[b] == *(a + b)
Therefore a[5] will evaluate to:
*(a + 5)
m>and m> 5[a] will evaluate to:
*(5 + a)
a is a pointer to the first element of the arram>y m>. a[5] is the value that's 5 el...
Multi-line tooltips in Java?
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If m>y m>ou wrap the tooltip in <html> m>and m> </html> tags, m>y m>ou can break lines with <br> tags. See http://www.jguru.com/faq/view.jsp?EID=10653 for examples m>and m> discussion.
Or m>y m>ou can use the JMultiLineToolTip class that can be found manm>y m> places on th...
How to get the changes on a branch in Git
...it-diff does not take a list of revisions - it takes one or two revisions, m>and m> has defined the A...B sm>y m>ntax to mean how it's defined in the git-diff manpage. If git-diff did not explicitlm>y m> define A...B, then that sm>y m>ntax would be invalid. Note that the git-rev-parse manpage describes A...B in the "Sp...