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Array versus linked-list
...t, i.e. that data structure that allows duplicate elements in an arbitrary order, that’s not suitable and you would have to go great lengths to make a data structure like LinkedList a concurrently updatable thing. If you only need a concurrent queue or deque, well yes, there are even existing exam...
Cannot create an array of LinkedLists in Java…?
...e the row map type a TreeMap, and same for traversing the columns in index order, but if you don't need those cases, HashMap is quicker than TreeMap. Helper methods to get and set an arbitrary cell, handling unset null values, would be useful, of course.
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Most efficient way to reverse a numpy array
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In order to have it working with negative numbers and a long list you can do the following:
b = numpy.flipud(numpy.array(a.split(),float))
Where flipud is for 1d arra
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Pandas get topmost n records within each group
... 2
3 7 3 1
4 8 4 1
(Keep in mind that you might need to order/sort before, depending on your data)
EDIT: As mentioned by the questioner, use df.groupby('id').head(2).reset_index(drop=True) to remove the multindex and flatten the results.
>>> df.groupby('id').head(2).res...
Java compile speed vs Scala compile speed
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You should be aware that Scala compilation takes at least an order of magnitude longer than Java to compile. The reasons for this are as follows:
Naming conventions (a file XY.scala file need not contain a class called XY and may contain multiple top-level classes). The compiler may ...
How to find Array length inside the Handlebar templates?
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If you are testing for an empty list in order to display content...
In Ember.js which uses handlebars, you can have an else for the #each.
{{#each blah as |blah|}}
{{else}}
// If array is empty
{{/each}}
...
SQL JOIN vs IN performance?
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That's rather hard to say - in order to really find out which one works better, you'd need to actually profile the execution times.
As a general rule of thumb, I think if you have indices on your foreign key columns, and if you're using only (or mostly) I...
What are libtool's .la file for?
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Does it mean that in order to generate .la file, I need to use libtool (e.g. from automake)? One can rely on libtool to link the object files (gnu.org/software/libtool/manual/html_node/Using-Automake.html) but if I want to distribute a library wi...
Facebook Open Graph not clearing cache
...488/…" that you need to have a Facebook like/share button on the page in order for the output of this end-point to contain any information.
– WillyBurb
Feb 17 '15 at 17:24
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What is the difference between XML and XSD?
...fines an element.
xs:sequence : Denotes child elements only appear in the order mentioned.
xs:complexType : Denotes it contains other elements.
xs:simpleType : Denotes they do not contain other elements.
type:
string,
decimal,
integer,
boolean,
date,
time,
In simple words, xsd is another way t...