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How to drop columns by name in a data frame
...t) %in% c("z","u"))] ## works as expected
dat[ , -which(names(dat) %in% c("foo","bar"))] ## deletes all columns! Probably not what you wanted...
Instead use subset or the ! function:
dat[ , !names(dat) %in% c("z","u")] ## works as expected
dat[ , !names(dat) %in% c("foo","bar")] ## returns the un...
R: Comment out block of code [duplicate]
...just put # signs in front of every line (possibly with editor shortcuts).
foo <- scan(what="character")
These are comments
These are still comments
Can also be code:
x <- 1:10
One line must be blank
rm(foo)
share
...
Linq to SQL how to do “where [column] in (list of values)”
...
Use
where list.Contains(item.Property)
Or in your case:
var foo = from codeData in channel.AsQueryable<CodeData>()
where codeIDs.Contains(codeData.CodeId)
select codeData;
But you might as well do that in dot notation:
var foo = channel.AsQueryable<Code...
How to determine when a Git branch was created?
...
Use
git show --summary `git merge-base foo master`
If you’d rather see it in context using gitk, then use
gitk --all --select-commit=`git merge-base foo master`
(where foo is the name of the branch you are looking for.)
...
Difference between __getattr__ vs __getattribute__
...ample based on Ned Batchelder's explanation.
__getattr__ example:
class Foo(object):
def __getattr__(self, attr):
print "looking up", attr
value = 42
self.__dict__[attr] = value
return value
f = Foo()
print f.x
#output >>> looking up x 42
f.x = 3
pr...
Can C++ code be valid in both C++03 and C++11 but do different things?
...
}
Operator new may now throw other exceptions than std::bad_alloc
struct foo { void *operator new(size_t x){ throw std::exception(); } }
try {
foo *f = new foo();
} catch (std::bad_alloc &) {
// c++03 code
} catch (std::exception &) {
// c++11 code
}
User-declared destructors ...
UnboundLocalError on local variable when reassigned after first use
...
The best example that makes it clear is:
bar = 42
def foo():
print bar
if False:
bar = 0
when calling foo() , this also raises UnboundLocalError although we will never reach to line bar=0, so logically local variable should never be created.
The mystery lies i...
Why does an NSInteger variable have to be cast to long when used as a format argument?
...nd all the casts and choosing the right string format specifier.
NSNumber foo = @9000;
NSLog(@"foo: %@", foo);
NSInteger bar = 9001;
NSLog(@"bar: %@", @(bar));
It also works for NSUIntegers without having to worry about that.
See answer to NSInteger and NSUInteger in a mixed 64bit / 32bit enviro...
Checking that a List is not empty in Hamcrest
...;
E.g. if you run
assertEquals(new ArrayList<>(0), Arrays.asList("foo", "bar");
you get
java.lang.AssertionError
Expected :[]
Actual :[foo, bar]
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Comparing two collections for equality irrespective of the order of items in them
...collections for equality.
/// </summary>
/// <param name="foo">The first collection.</param>
/// <param name="bar">The second collection.</param>
/// <returns>True if both collections have the same content, false otherwise.</returns>
publ...