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Android Emulator: Installation error: INSTALL_FAILED_VERSION_DOWNGRADE
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It means you're trying to install an app with the same packageName as an app that's already installed on the emulator, but the one you're trying to install has a lower versionCode (integer value for your version number).
You mi...
How to insert a row in an HTML table body in JavaScript
...nto the tbody, get a reference to it and add it there.
var tableRef = document.getElementById('myTable').getElementsByTagName('tbody')[0];
// Insert a row in the table at the last row
var newRow = tableRef.insertRow();
// Insert a cell in the row at index 0
var newCell = newRow.insertCell(0);
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Disable ActiveRecord for Rails 4
... your config/application.rb
Remove require 'rails/all line and require frameworks (among those available in your rails version, the list varies, do not just copy) you want to use, for example:
require "action_controller/railtie"
require "action_mailer/railtie"
require "sprockets/railtie"
require "...
Lisp in the real world
I have experimented with Lisp (actually Scheme) and found it to be a very beautiful language that I am interested in learning more about. However, it appears that Lisp is never used in serious projects, and I haven't seen it listed as a desired skill on any job posting. I am interested in hearing ...
Why does Eclipse complain about @Override on interface methods?
I have an existing project that uses @Override on methods that override interface methods, rather than superclass methods. I cannot alter this in code, but I would like Eclpse to stop complaining about the annotation, as I can still build with Maven.
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Pick a random value from an enum?
...s() because each call copies an array. Also, don't create a Random every time. Keep one. Other than that what you're doing is fine. So:
public enum Letter {
A,
B,
C,
//...
private static final List<Letter> VALUES =
Collections.unmodifiableList(Arrays.asList(values()));
privat...
How to read if a checkbox is checked in PHP?
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If your HTML page looks like this:
<input type="checkbox" name="test" value="value1">
After submitting the form you can check it with:
isset($_POST['test'])
or
if ($_POST['test'] == 'value1') ...
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HTTP requests and JSON parsing in Python
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I recommend using the awesome requests library:
import requests
url = 'http://maps.googleapis.com/maps/api/directions/json'
params = dict(
origin='Chicago,IL',
destination='Los+Angeles,CA',
waypoints='Joplin,MO|Oklaho...
How to change an input button image using CSS?
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Rearrange columns using cut
...y ranges separated by commas. Selected input is written
in the same order that it is read, and is written exactly once.
It reaches field 1 first, so that is printed, followed by field 2.
Use awk instead:
awk '{ print $2 " " $1}' file.txt
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