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Order data frame rows according to vector with specific order
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236
Try match:
df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
targe...
What's the difference between array_merge and array + array?
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72
The difference is:
The + operator takes the union of the two arrays, whereas the array_merge fu...
How to print a number with commas as thousands separators in JavaScript
...th commas as thousands separators. For example, I want to show the number 1234567 as "1,234,567". How would I go about doing this?
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Difference between open and codecs.open in Python
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Since Python 2.6, a good practice is to use io.open(), which also takes an encoding argument, like the now obsolete codecs.open(). In Python 3, io.open is an alias for the open() built-in. So io.open() works in Python 2.6 and all later ve...
Is there a difference between foreach and map?
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295
Different.
foreach iterates over a list and applies some operation with side effects to each ...
How do I do multiple CASE WHEN conditions using SQL Server 2008?
... many WHEN as;
CASE WHEN Col1 = 1 OR Col3 = 1 THEN 1
WHEN Col1 = 2 THEN 2
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ELSE 0 END as Qty
Or a Simple CASE expression
CASE Col1 WHEN 1 THEN 11 WHEN 2 THEN 21 ELSE 13 END
Or CASE within CASE as;
CASE WHEN Col1 < 2 THEN
CASE Col2 WHEN 'X' THE...
How to install plugins to Sublime Text 2 editor?
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182
You should have a Data/Packages folder in your Sublime Text 2 install directory.
All you need to...
Pandas DataFrame column to list [duplicate]
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270
You can use the Series.to_list method.
For example:
import pandas as pd
df = pd.DataFrame({...
Finding quaternion representing the rotation from one vector to another
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Quaternion q;
vector a = crossproduct(v1, v2);
q.xyz = a;
q.w = sqrt((v1.Length ^ 2) * (v2.Length ^ 2)) + dotproduct(v1, v2);
Don't forget to normalize q.
Richard is right about there not being a unique rotation, but the above should give the "shortest arc," which ...