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Adding a column to an existing table in a Rails migration
...cord::Migration[5.0]
def change
end
end
In that case you have to manually an add_column to change:
class AddEmailToUsers < ActiveRecord::Migration[5.0]
def change
add_column :users, :email, :string
end
end
And then run rake db:migrate
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JavaScript variable assignments from tuples
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Javascript 1.7 added destructured assignment which allows you to do essentially what you are after.
function getTuple(){
return ["Bob", 24];
}
var [a, b] = getTuple();
// a === "bob" , b === 24 are both true
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Apache redirect to another port
...//example.com in ProxyPass and ProxyPassReverse and leave it as /. Additionally, you need to leave the / at the end of example/ to where it is redirecting. Also, I had some trouble with http://example.com vs. http://www.example.com - only the www worked until I made the ServerName www.example.com, a...
How do I get the 'clear' command in Cygwin?
I installed Cygwin, choosing a fairly minimal set of packages.
10 Answers
10
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Add x and y labels to a pandas plot
...el", ylabel="y label").
Alternatively, the index x-axis label is automatically set to the Index name, if it has one. so df2.index.name = 'x label' would work too.
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Simulating tremor (from e.g. Parkinson's Disease) with the mouse on a webpage?
...or accessibility in the internet. For a presentation, we want to offer a small workshop that simulates different disabilities/impairments to people. This is done via a website created especially for this presentation.
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Making iTerm to translate 'meta-key' in the same way as in other OSes
... to move one word forward or backward on the shell prompt respectively. Usually, the meta key is mapped to Alt key on Windows and Linux. However, in iTerm, I could not find a way to map this meta key to either Option or Command key on my MacBook Pro.
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Android Fragment handle back button press [duplicate]
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When you are transitioning between Fragments, call addToBackStack() as part of your FragmentTransaction:
FragmentTransaction tx = fragmentManager.beginTransation();
tx.replace( R.id.fragment, new MyFragment() ).addToBackStack( "tag" ).commit();
If you require more deta...
Cluster analysis in R: determine the optimal number of clusters
...lidean",
method = "kmeans", min.nc=2, max.nc=15,
index = "alllong", alphaBeale = 0.1)
hist(nb$Best.nc[1,], breaks = max(na.omit(nb$Best.nc[1,])))
# Looks like 3 is the most frequently determined number of clusters
# and curiously, four clusters is not in the output at all!
If yo...
How do you version your database schema? [closed]
How do you prepare your SQL deltas? do you manually save each schema-changing SQL to a delta folder, or do you have some kind of an automated diffing process?
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