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Is null reference possible?
...
References are not pointers.
8.3.2/1:
A reference shall be initialized to
refer to a valid object or function.
[Note: in particular, a null reference
cannot exist in a well-defined
program, because the only way to
create such a reference would be to
bind it to the ...
Import multiple csv files into pandas and concatenate into one DataFrame
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If you have same columns in all your csv files then you can try the code below.
I have added header=0 so that after reading csv first row can be assigned as the column names.
import pandas as pd
import glob
path = r'C:\DRO\DCL_rawdata_files' # use you...
How do I list loaded plugins in Vim?
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Not a VIM user myself, so forgive me if this is totally offbase. But according to what I gather from the following VIM Tips site:
" where was an option set
:scriptnames : list all plugins, _vimrcs loaded (super)
:verbose set history? : reveals value of hist...
Automatic Retina images for web sites
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There is a new attribute for the img tag that allows you to add a retina src attribute, namely srcset. No javascript or CSS needed, no double loading of images.
<img src="low-res.jpg" srcset="high-res.jpg 2x">
Browser Support: http://caniuse.com/#search=srcset
O...
How do you create nested dict in Python?
...he following:
d = {} # can use defaultdict(dict) instead
for row in file_map:
# derive row key from something
# when using defaultdict, we can skip the next step creating a dictionary on row_key
d[row_key] = {}
for idx, col in enumerate(row):
d[row_key][idx] = col
Ac...
Get item in the list in Scala?
...
Use parentheses:
data(2)
But you don't really want to do that with lists very often, since linked lists take time to traverse. If you want to index into a collection, use Vector (immutable) or ArrayBuffer (mutable) or possibly Array (which is just a Java array, exc...
How to convert a SVG to a PNG with ImageMagick?
... to convert it into a PNG, then I get a 16x16 pixel PNG which is way too small:
18 Answers
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Why does the default parameterless constructor go away when you create one with parameters
...ass, I most likely want to be able to instantiate that class. In order to allow that, the compiler must add a parameterless constructor, which will have no effect but to allow instantiation. This means that I don't have to include an empty constructor in my code just to make it work.
If I've defin...
What Every Programmer Should Know About Memory?
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So, any book or article that describes something fundamental cannot be called outdated. "What every programmer should know about memory" is definitely worth to read, but, well, I don't think it's for "every programmer". It's more suitable for system/embedded/kernel guys.
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machine learning libraries in C# [closed]
...asses:
public class TrainingSet
{
private readonly List<string> _attributes = new List<string>();
private readonly List<List<object>> _examples = new List<List<object>>();
public TrainingSet(params string[] attributes)
{
_attributes.AddRang...