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Drop unused factor levels in a subsetted data frame
...- factor(subdf$letters)
> subdf$letters
[1] a b c
Levels: a b c
EDIT
From the factor page example:
factor(ff) # drops the levels that do not occur
For dropping levels from all factor columns in a dataframe, you can use:
subdf <- subset(df, numbers <= 3)
subdf[] <- lapply(subd...
_DEBUG vs NDEBUG
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NDEBUG isn't defined when using applications templates from Windows Driver Kit 8.1 too. In this case, you may need to rely on _DEBUG.
– navossoc
Apr 7 '16 at 15:36
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Why hasn't functional programming taken over yet?
... programming (languages), tried out Haskell as well as written one myself. From what I've seen, functional programming has several advantages over the classical imperative style:
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Is it good practice to use java.lang.String.intern()?
...ppropriate strings on input so you don't have to worry about it anymore.
(from JGuru)
Third disadvantage (Java 7 or less only): interned Strings live in PermGen space, which is usually quite small; you may run into an OutOfMemoryError with plenty of free heap space.
(from Michael Borgwardt)
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Pros and cons of Java rules engines [closed]
...and Drools?
Use a rule engine if you need to separate the business rules from the application logic. The Does Your Project Need a Rule Engine article has a good example:
For example, a typical storefront
system might involve code to calculate
a discount:
if (product.quantity > 100 &...
How to get the current branch name in Git?
I'm from a Subversion background and, when I had a branch, I knew what I was working on with "These working files point to this branch".
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How can I move a single directory from a git repository to a new repository whilst maintaining the h
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You can use git filter-branch to rewrite the history of a project. From the documentation:
To rewrite the repository to look as
if foodir/ had been its project root,
and discard all other history:
git filter-branch --subdirectory-filter foodir -- --all
Make several copies of your...
How do I find the current executable filename? [duplicate]
...which could be the same assembly as above, if your code is called directly from a class within your executable):
System.Reflection.Assembly.GetCallingAssembly().Location
If you'd like just the filename and not the path, use:
Path.GetFileName(System.Reflection.Assembly.GetEntryAssembly().Location...
Retrieve the position (X,Y) of an HTML element relative to the browser window
... If you need it relative to another element, simply subtract one rectangle from the other:
var bodyRect = document.body.getBoundingClientRect(),
elemRect = element.getBoundingClientRect(),
offset = elemRect.top - bodyRect.top;
alert('Element is ' + offset + ' vertical pixels from <bod...
How do I build a numpy array from a generator?
...One google behind this stackoverflow result, I found that there is a numpy.fromiter(data, dtype, count). The default count=-1 takes all elements from the iterable. It requires a dtype to be set explicitly. In my case, this worked:
numpy.fromiter(something.generate(from_this_input), float)
...