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Get generic type of java.util.List
...yCollection.stream()
.filter(Objects::nonNull)
.collect(Collectors.groupingBy(Object::getClass));
// Process the list of the correct class, and/or handle objects of incorrect
// class (throw exceptions, etc). You may need to group subclasses by
// filtering the keys. For instance:
List<...
How to get the last N rows of a pandas DataFrame?
...__getitem__).
As an aside, if you want to find the last N rows for each group, use groupby and GroupBy.tail:
df.groupby('A').tail(2)
A B
1 a 2
2 a 3
5 b 6
6 b 7
7 c 8
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imp...
What is the difference between Collection and List in Java?
... root interface in the collection
hierarchy. A collection represents a
group of objects, known as its
elements. Some collections allow
duplicate elements and others do not.
Some are ordered and others unordered.
The JDK does not provide any direct
implementations of this interface: it
...
How to Correctly Use Lists in R?
... hash package. You can read about it in this blog post from the Open Data Group. Here's a simple example:
> library(hash)
> h <- hash( keys=c('foo','bar','baz'), values=1:3 )
> h[c('foo','bar')]
<hash> containing 2 key-value pairs.
bar : 2
foo : 1
In terms of usability, th...
Maven: best way of linking custom external JAR to my project?
....basedir}/libs</url>
</repository>
<dependency>
<groupId>dropbox</groupId>
<artifactId>dropbox-sdk</artifactId>
<version>1.3.1</version>
</dependency>
/groupId/artifactId/version/artifactId-verion.jar
detail read this blog p...
Usage of forceLayout(), requestLayout() and invalidate()
...ceLayout()
When there is a requestLayout() that is called on a parent view group, it does not necessary need to remeasure and relayout its child views. However, if a child should be included in the remeasure and relayout, then you can call forceLayout() on the child. forceLayout() only works on a ch...
How do you get the logical xor of two variables in Python?
...Also, there's a difference between a three-way XOR vs. order-of-operations-grouped set of two XORs. So 3-WAY-XOR(A,B,C) is not the same thing as XOR(XOR(A,B),C). And ddaa's example is the former, while yours assumes the latter.
– ely
Oct 23 '12 at 21:20
...
Differences between MySQL and SQL Server [closed]
...
Group_concat and REGEXP are more than enough reasons to use MySQL over SQL Server (even if the two licences were switched)
– Michele
Feb 24 '15 at 11:51
...
Anyone else find naming classes and methods one of the most difficult parts in programming? [closed]
...sy if you have multiple Gets in the same class as unrelated things will be grouped together.
I akin this to naming files with dates, you want to say 2009-01-07.log not 1-7-2009.log because after you have a bunch of them, the order becomes totally useless.
...
leiningen - how to add dependencies for local jars?
...en, Clojure and libraries: what am I missing? thread on the Clojure Google group. Many participants specifically mention the need to have local dependencies not contained in any repositories, local or otherwise, and elaborate on the solutions they've come up with for such scenarios. Perhaps you coul...