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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...
Maven Install on Mac OS X
I'm trying to install maven through the terminal by following these instructions .
24 Answers
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Ruby send vs __send__
I understand the concept of some_instance.send but I'm trying to figure out why you can call this both ways. The Ruby Koans imply that there is some reason beyond providing lots of different ways to do the same thing. Here are the two examples of usage:
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How to rsync only a specific list of files?
... for me using the --include-from option. Without the --exclude="*" option, all the files in the directory are being synced, with the option, no files are.
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Get the name of the currently executing method
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Even better than my first answer you can use __method__:
class Foo
def test_method
__method__
end
end
This returns a symbol – for example, :test_method. To return the method name as a string, call __method__.to_s instead.
Note: This requires Ruby 1.8.7.
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Counting the Number of keywords in a dictionary in python
... the len() function.
> a = {'foo':42, 'bar':69}
> len(a)
2
To get all the distinct words (i.e. the keys), use the .keys() method.
> list(a.keys())
['foo', 'bar']
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Difference between Repository and Service Layer?
... bool Delete(int id);
T Get(int id);
bool SaveChanges();
}
and call Get(id). Repository layer exposes basic CRUD operations.
Service layer exposes business logic, which uses repository. Example service could look like:
public interface IUserService
{
User GetByUserName(string userNa...
Matplotlib (pyplot) savefig outputs blank image
...values that depend whether or not T0 exists.
Second, after plt.show() is called, a new figure is created. To deal with this, you can
Call plt.savefig('tessstttyyy.png', dpi=100) before you call plt.show()
Save the figure before you show() by calling plt.gcf() for "get current figure", then you ca...
Python: split a list based on a condition?
What's the best way, both aesthetically and from a performance perspective, to split a list of items into multiple lists based on a conditional? The equivalent of:
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What is :: (double colon) in Python when subscripting sequences?
... @UmarAsghar n means start. so the list start from nth index. Basically, [start:stop:step]
– harryghgim
Sep 1 at 11:42
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