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SQL RANK() versus ROW_NUMBER()
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229
ROW_NUMBER : Returns a unique number for each row starting with 1. For rows that have duplicat...
How to create an object for a Django model with a many to many field?
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248
You cannot create m2m relations from unsaved objects. If you have the pks, try this:
sample_o...
What would cause an algorithm to have O(log n) complexity?
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290
I have to agree that it's pretty weird the first time you see an O(log n) algorithm... where o...
Weighted random numbers
...e items have individual weights:
1) calculate the sum of all the weights
2) pick a random number that is 0 or greater and is less than the sum of the weights
3) go through the items one at a time, subtracting their weight from your random number, until you get the item where the random number is ...
Iterating over Java collections in Scala
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28
There is a wrapper class (scala.collection.jcl.MutableIterator.Wrapper). So if you define
imp...
Pandas: create two new columns in a dataframe with values calculated from a pre-existing column
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2 Answers
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Sorting arrays in NumPy by column
...ck example, to sort it and return a copy:
In [1]: import numpy as np
In [2]: a = np.array([[1,2,3],[4,5,6],[0,0,1]])
In [3]: np.sort(a.view('i8,i8,i8'), order=['f1'], axis=0).view(np.int)
Out[3]:
array([[0, 0, 1],
[1, 2, 3],
[4, 5, 6]])
To sort it in-place:
In [6]: a.view('i8,i8...
How to make lists contain only distinct element in Python? [duplicate]
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278
The simplest is to convert to a set then back to a list:
my_list = list(set(my_list))
One d...
Centering the pagination in bootstrap
...t;
<li><a href="?p=1" data-original-title="" title="">2</a></li>
</ul>
</div>
Bootstrap 4 has new class
<div class="text-xs-center">
<ul class="pagination">
<li><a href="?p=0" data-original-title="" title="">1&l...
Write a number with two decimal places SQL server
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218
try this
SELECT CONVERT(DECIMAL(10,2),YOURCOLUMN)
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