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Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
Coding Practices which enable the compiler/optimizer to make a faster program
...act.
Expect to be disappointed and to have to work very hard indeed for small performance improvements. Modern compilers for mature languages such as Fortran and C are very, very good. If you read an account of a 'trick' to get better performance out of code, bear in mind that the compiler writer...
Modifying the “Path to executable” of a windows service
... answered Jul 22 '14 at 0:33
Niall ConnaughtonNiall Connaughton
13.5k1010 gold badges4848 silver badges4646 bronze badges
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How to delete or add column in SQLITE?
...upports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.
You can:
create new table as the one you ar...
Where are static variables stored in C and C++?
...
@Don Neufeld: your answer does not answer the question at all. I do not understand why it is accepted. Because the both the 'foo' and 'bar' are non-0 initialized. The question is where to place two static/global variable with the same name in .bss or .data
– lu...
Referencing system.management.automation.dll in Visual Studio
...g it updated, releasing new packages, etc.
– Ben Randall
Feb 5 '16 at 19:24
last updated 29/03/2013 " The owner has un...
What is the copy-and-swap idiom?
...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
How does it wor...
Generate random numbers using C++11 random library
... functions and why not to use rand(). In it, he included a slide that basically solves your question. I've copied the code from that slide below.
You can see his full talk here: http://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful
#include <random>
#include <iostream&g...
How to change field name in Django REST Framework
...get_alternate_name(self, obj):
return obj.alternate_name
Additionally, you can use serializers.CharField with source attribute:
class ParkSerializer(serializers.ModelSerializer):
location = serializers.CharField(source='other_fields')
class Meta:
model = Park
fiel...
What is the use for Task.FromResult in C#
In C# and TPL ( Task Parallel Library ), the Task class represents an ongoing work that produces a value of type T.
6 Ans...