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Pandas: drop a level from a multi-level column index?
...
You can use MultiIndex.droplevel:
>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ("a", "c")])
>>> df = pd.DataFrame([[1,2], [3,4]], columns=cols)
>>> df
a
b c
0 1 2
1 3 4
[2 rows x 2 columns]
>>> df.columns = df.columns.droplevel()
>>>...
iPhone viewWillAppear not firing
...
Swift 3: func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {} AND func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewControl...
How to access the correct `this` inside a callback?
...ontrived example:
var arr = [1, 2, 3];
var obj = {multiplier: 42};
var new_arr = arr.map(function(v) {
return v * this.multiplier;
}, obj); // <- here we are passing `obj` as second argument
Note: Whether or not you can pass a value for this is usually mentioned in the documentation of that...
How can I create a UILabel with strikethrough text?
...for strikethrough Enable/Disable.
extension UILabel {
func strikeThrough(_ isStrikeThrough:Bool) {
if isStrikeThrough {
if let lblText = self.text {
let attributeString = NSMutableAttributedString(string: lblText)
attributeString.addAttribute(NSAttributedString...
Compiling simple Hello World program on OS X via command line
...e ld: can't link with a main executable file './a.out' for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
– Eddified
Jan 31 '14 at 6:32
...
Sorting an array of objects in Ruby by object attribute?
...
I recommend using sort_by instead:
objects.sort_by {|obj| obj.attribute}
Especially if attribute may be calculated.
Or a more concise approach:
objects.sort_by(&:attribute)
...
How to construct a std::string from a std::vector?
...in VS2013 which asserts at runtime about invalid iterators, unless you set _ITERATOR_DEBUG_LEVEL=1 (in which case it seems to work fine).
– Cameron
Sep 23 '14 at 22:39
add a c...
How to remove all the occurrences of a char in c++ string
...on for you, like:
#include <boost/algorithm/string.hpp>
boost::erase_all(str, "a");
All of this is well-documented on reference websites. But if you didn't know of these functions, you could easily do this kind of things by hand:
std::string output;
output.reserve(str.size()); // optional,...
Generating v5 UUID. What is name and namespace?
...ce of having a single collision.
See http://en.wikipedia.org/wiki/Birthday_problem#Probability_table for the probability table.
See http://www.ietf.org/rfc/rfc4122.txt for more details on UUID encodings.
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Bundler: Command not found
...t found: bundle
λ ruby -v
ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
### Notice the system Ruby version isn't included in chruby
λ chruby
ruby-1.9.3-p551
ruby-2.1.2
ruby-2.2.1
### Select a version via your version manager
λ chruby 1.9.3
### Ensure your version manager p...