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Want to find records with no associated records in Rails
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This is still pretty close to SQL, but it should get everyone with no friends in the first case:
Person.where('id NOT IN (SELECT DISTINCT(person_id) FROM friends)')
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How do I calculate percentiles with python/numpy?
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You might be interested in the SciPy Stats package. It has the percentile function you're after and many other statistical goodies.
percentile() is available in numpy too.
import numpy as np
a = np.array([1,2,3,4,5])
p = np.percentile(a, 50) # return 50th percentile, e.g med...
How to deploy correctly when using Composer's develop / production switch?
...oject is started: composer.phar install --dev, json and lock files are commited to VCS.
Other developers start working on the project: checkout of VCS and composer.phar install --dev.
A developer adds dependancies: composer.phar require <package>, add --dev if you want the package in the requi...
PostgreSQL: How to make “case-insensitive” query
Is there any way to write case-insensitive queries in PostgreSQL, E.g. I want that following 3 queries return same result.
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How to stop a PowerShell script on the first error?
...great for cmdlets).
However for EXEs you're going to need to check $LastExitCode yourself after every exe invocation and determine whether that failed or not. Unfortunately I don't think PowerShell can help here because on Windows, EXEs aren't terribly consistent on what constitutes a "success" or ...
Removing an activity from the history stack
My app shows a signup activity the first time the user runs the app, looks like:
15 Answers
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The ALTER TABLE statement conflicted with the FOREIGN KEY constraint
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It occurred because you tried to create a foreign key from tblDomare.PersNR to tblBana.BanNR but/and the values in tblDomare.PersNR didn't match with any of the values in tblBana.BanNR. You cannot create a relation which viol...
How does node.bcrypt.js compare hashed and plaintext passwords without the salt?
From github :
3 Answers
3
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Install Windows Service created in Visual Studio
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You need to open the Service.cs file in the designer, right click it and choose the menu-option "Add Installer".
It won't install right out of the box... you need to create the installer class first.
Some reference on service installer:
How to: Add Installers to Your Service Application
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How do you change the datatype of a column in SQL Server?
...BLE TableName
ALTER COLUMN ColumnName NVARCHAR(200) [NULL | NOT NULL]
EDIT
As noted NULL/NOT NULL should have been specified, see Rob's answer as well.
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