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Overriding fields or properties in subclasses
I have an abstract base class and I want to declare a field or a property that will have a different value in each class that inherits from this parent class.
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SET versus SELECT when assigning variables?
What are the differences between the SET and SELECT statements when assigning variables in T-SQL?
4 Answers
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Remove duplicated rows using dplyr
...mple(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_number(z) == 1)
## Source: local data frame [3 x 3]
## Groups: x, y
##
## x y z
## 1 0 1 1
## 2 1 0 2
## 3 1 1 4
(In dplyr 0.2 you won't need...
How do I retrieve the number of columns in a Pandas data frame?
How do you programmatically retrieve the number of columns in a pandas dataframe? I was hoping for something like:
6 Answer...
Long Press in JavaScript?
...at, you don't just want mouse move though - holding you finger dead steady and not moving 1px is quite hard! You need to apply a threshold (if mouse hasn't moved 10px) etc. Gets complicated quite quickly!
– Ian
Feb 18 '15 at 12:44
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How do you dynamically add elements to a ListView on Android?
...anyone explain or suggest a tutorial to dynamically create a ListView in android?
7 Answers
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How to find event listeners on a DOM node when debugging or from the JavaScript code?
I have a page where some event listeners are attached to input boxes and select boxes. Is there a way to find out which event listeners are observing a particular DOM node and for what event?
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How do I compute derivative using Numpy?
...es
Automatic Derivatives
Symbolic Differentiation
Compute derivatives by hand.
Finite differences require no external tools but are prone to numerical error and, if you're in a multivariate situation, can take a while.
Symbolic differentiation is ideal if your problem is simple enough. Symbolic...
Differences between Html.TextboxFor and Html.EditorFor in MVC and Razor
...te a custom editor template (~/Views/Shared/EditorTemplates/string.cshtml) and all your textboxes in your application will automatically benefit from this change whereas if you have hardcoded Html.TextBoxFor you will have to modify it everywhere. You could also use Data Annotations to control the wa...
How do I break out of a loop in Scala?
...> sum+=i)
(warning--this depends on details of how the takeWhile test and the foreach are interleaved during evaluation, and probably shouldn't be used in practice!).
(1b) Use tail recursion instead of a for loop, taking advantage of how easy it is to write a new method in Scala:
var sum = 0
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