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Array slicing in Ruby: explanation for illogical behaviour (taken from Rubykoans.com)
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10 Answers
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How are feature_importances in RandomForestClassifier determined?
...data used on the tree?
– Cokes
Jan 20 '15 at 20:27
1
Two useful resources. (1) blog.datadive.net/...
How do I truncate a .NET string?
...lue;
return value.Length <= maxLength ? value : value.Substring(0, maxLength);
}
}
Now we can write:
var someString = "...";
someString = someString.Truncate(2);
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Generate a random point within a circle (uniformly)
...andom point on BC. Ie. pick a pair of random numbers x and y uniformly on [0,R] giving distances from the center. Our triangle is a thin sliver so AB and BC are essentially parallel. So the point Z is simply a distance x+y from the origin. If x+y>R we fold back down.
Here's the complete algorith...
Resizing an image in an HTML5 canvas
...lement them yourself then! Oh come on, we're entering the new age of Web 3.0, HTML5 compliant browsers, super optimized JIT javascript compilers, multi-core(†) machines, with tons of memory, what are you afraid of? Hey, there's the word java in javascript, so that should guarantee the performance,...
Pandas: drop a level from a multi-level column index?
...pd.DataFrame([[1,2], [3,4]], columns=cols)
>>> df
a
b c
0 1 2
1 3 4
[2 rows x 2 columns]
>>> df.columns = df.columns.droplevel()
>>> df
b c
0 1 2
1 3 4
[2 rows x 2 columns]
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What ports does RabbitMQ use?
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edited Sep 19 '14 at 18:00
Eric Leschinski
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Specifying rails version to use when creating a new application
I have two versions of rails (2.1.0 and 2.2.2) installed in my computer.
7 Answers
7
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RegEx for Javascript to allow only alphanumeric
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/^[a-z0-9]+$/i
^ Start of string
[a-z0-9] a or b or c or ... z or 0 or 1 or ... 9
+ one or more times (change to * to allow empty string)
$ end of string
/i case-insensitive
Update (supporting ...
How to check whether a pandas DataFrame is empty?
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505
You can use the attribute df.empty to check whether it's empty or not:
if df.empty:
print(...