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Reason for Column is invalid in the select list because it is not contained in either an aggregate f
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Suppose I have the following table T:
a b
--------
1 abc
1 def
1 ghi
2 jkl
2 mno
2 pqr
And I do the following query:
SELECT a, b
FROM T
GROUP BY a
The output should have two rows, one row where a=1 and a second row where a=2.
But what ...
How to take column-slices of dataframe in pandas
... load some machine learning data from a CSV file. The first 2 columns are observations and the remaining columns are features.
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How can I get a count of the total number of digits in a number?
How can I get a count of the total number of digits of a number in C#? For example, the number 887979789 has 9 digits.
16 A...
How to identify numpy types in python?
How can one reliably determine if an object has a numpy type?
6 Answers
6
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What is compiler, linker, loader?
...king of compiler, linker and loader.
With reference to any language preferably c++.
14 Answers
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Solving “Who owns the Zebra” programmatically?
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Here's a solution in Python based on constraint-programming:
from constraint import AllDifferentConstraint, InSetConstraint, Problem
# variables
colors = "blue red green white yellow".split()
nationalities = "Norwegian German Dane Swede Engli...
Negative weights using Dijkstra's Algorithm
...rithm you have suggested will indeed find the shortest path in this graph, but not all graphs in general. For example, consider this graph:
Assume the edges are directed from left to right as in your example,
Your algorithm will work as follows:
First, you set d(A) to zero and the other dista...
sort object properties and JSON.stringify
My application has a large array of objects, which I stringify and save them to the disk. Unfortunately, when the objects in the array are manipulated, and sometimes replaced, the properties on the objects are listed in different orders (their creation order?). When I do JSON.stringify() on the arr...
Is there a performance gain in using single quotes vs double quotes in ruby?
Do you know if using double quotes instead of single quotes in ruby decreases performance in any meaningful way in ruby 1.8 and 1.9.
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u'\ufeff' in Python string
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The Unicode character U+FEFF is the byte order mark, or BOM, and is used to tell the difference between big- and little-endian UTF-16 encoding. If you decode the web page using the right codec, Python will remove it for you. Examples:
#!python2
#coding: utf8...