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Prepend a level to a pandas MultiIndex
...
It took me a while to realize that if you have more than one key for FirstLevel as in ['Foo', 'Bar'] the first argument will also need to have the corresponding length, i.e., [df] * len(['Foo', 'Bar'])!
– mrclng
Dec 13 '1...
Java - No enclosing instance of type Foo is accessible
...ch (by definition) is associated with a particular instance of Hello (even if it never uses or refers to it), which means it's an error to say new Thing(); without having a particular Hello instance in scope.
If you declare it as a static class instead, then it's a "nested" class, which doesn't ne...
Java 8 Streams: multiple filters vs. complex condition
...aryStatistics{count=100, sum=10320, min=82, average=103.200000, max=127}
now the code:
enum Gender {
FEMALE,
MALE
}
static class User {
Gender gender;
int age;
public User(Gender gender, int age){
this.gender = gender;
this.age = age;
}
public Gender...
How to generate the JPA entity Metamodel?
...
It would be awesome if someone also knows the steps for setting this up in Eclipse (I assume it's as simple as setting up an annotation processor, but you never know)
Yes it is. Here are the implementations and instructions for the various JPA...
NSObject +load and +initialize - What do they do?
...able file, the runtime sends the load message very early in the process's lifetime. For classes that are in a shared (dynamically-loaded) library, the runtime sends the load message just after the shared library is loaded into the process's address space.
Furthermore, the runtime only sends load t...
What does passport.session() middleware do?
...hilst the other answers make some good points I thought that some more specific detail could be provided.
app.use(passport.session());
is equivalent to
app.use(passport.authenticate('session'));
Where 'session' refers to the following strategy that is bundled with passportJS.
https://github....
How to specify the default error page in web.xml?
I am using <error-page> element in web.xml to specify the friendly error page when user encounters a certain error such as error with code of 404:
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Compression/Decompression string with C#
...r1);
}
Remember that Zip returns a byte[], while Unzip returns a string. If you want a string from Zip you can Base64 encode it (for example by using Convert.ToBase64String(r1)) (the result of Zip is VERY binary! It isn't something you can print to the screen or write directly in an XML)
The vers...
Is it .yaml or .yml?
...ioned factors may have been the main ones; nevertheless, all the factors (known or unknown) have resulted in the abbreviated, three (3) character extension becoming the one in predominant use for YAML—despite the inventors' preference.
".YML" seems to be the de facto standard. Yet the same invent...
Fastest way to iterate over all the chars in a String
...tarting from Java 9, the solution as described won't work anymore, because now Java will store strings as byte[] by default.
SECOND UPDATE: As of 2016-10-25, on my AMDx64 8core and source 1.8, there is no difference between using 'charAt' and field access. It appears that the jvm is sufficiently opt...