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How to return an empty ActiveRecord relation?
...and it takes an argument, depending on the value of the argument, I might know that there will not be any matches, but I still want to return a relation, not an empty array:
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How do I install the yaml package for Python?
...Note that PySyck docs recommend using PyYaml, since syck is out of date). Now you know a specific package name, you can install it:
$ pip install pyyaml
If you want to install python yaml system-wide in linux, you can also use a package manager, like aptitude or yum:
$ sudo apt-get install pyth...
How do I print the type of a variable in Rust?
... used to be as simple as 32.90.eq(&32.90), but that treats both as f64 now and chugs along happily, so I don’t know.
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How to calculate the running time of my program? [duplicate]
I wrote a program and now I want to calculate the total running time of my program from start to end.
6 Answers
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How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...ou're on 9.5 and don't need to be backward-compatible you can stop reading now.
9.4 and older:
PostgreSQL doesn't have any built-in UPSERT (or MERGE) facility, and doing it efficiently in the face of concurrent use is very difficult.
This article discusses the problem in useful detail.
In general y...
Switch branch names in git
...ed from before I started my crap work. Practically this works fine, I just now have a different branch as my main development branch. I'm wondering how I could change things around so I'm working on master again but it doesn't have my junk work and said work is on a different branch.
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Can unit testing be successfully added into an existing production project? If so, how and is it wor
... months ago before I could really see any benefit of TDD (face palm) , so now it's a rather large solution with a number of projects and I haven't the foggiest idea where to start in adding unit tests. What's making me consider this is that occasionally an old bug seems to resurface, or a bug is ch...
What is the difference between location list and quickfix list in vim
...us to move through those lists without opening the associated windows and knowing the difference between those lists is key to using those commands efficiently.
Hands-on illustrated example:
Do :lvim foo % in foo.txt to create a location list for the window containing foo.txt.
Do :lne a few ti...
How To Set A JS object property name from a variable
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Also note that @ChilNut's response below now describes the easiest way of doing this using ES6
– rambossa
Jan 28 '16 at 14:34
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What does “./bin/www” do in Express 4.x?
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Because the app.js file that was generated by the Express 4 generator is now a Node.js module, it can no longer be started independently as an app (unless you modify the code). The module must be loaded in a Node.js file and started via the Node.js file. The Node.js file is ./bin/www in this case....