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PG undefinedtable error relation users does not exist
...llowing:
rake db:reset
The rake db:reset task will drop the database and set it up again. This is functionally equivalent to rake db:drop db:setup.
This is not the same as running all the migrations. It will only use the
contents of the current schema.rb file. If a migration can't be ro...
How to escape double quotes in JSON
... within the quotation marks except for the characters that must be escaped and then it specifies: \" represents the quotation mark character (U+0022)
– mastazi
Mar 30 '17 at 1:30
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Create and append dynamically
...id='block'> you've created. You just need to create another <div> and call appendChild().
// Your existing code unmodified...
var iDiv = document.createElement('div');
iDiv.id = 'block';
iDiv.className = 'block';
document.getElementsByTagName('body')[0].appendChild(iDiv);
// Now create an...
When to use an object instance variable versus passing an argument to the method
...To some degree, when to use instance variables, how to define their scope, and when to use local variables is subjective, but there are a couple of rules of thumb you can follow whenever creating your classes.
Instance variables are typically considered to be attributes of a class. Think of these ...
Why does Android use Java? [closed]
...
Some points:
Java is a known language, developers know it and don't have to learn it
it's harder to shoot yourself with Java than with C/C++ code since it has no pointer arithmetic
it runs in a VM, so no need to recompile it for every phone out there and easy to secure
large number ...
How to get current foreground activity context in android?
... still return a small subset of its data: at least the caller's own tasks, and possibly some other tasks such as home that are known to not be sensitive.
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Why is \r a newline for Vim?
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For me the point of confusion is that \r and \n mean different things when used is the search pattern and the replacement pattern.
– dlamblin
Dec 4 '12 at 17:09
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Using PropertyInfo to find out the property type
... validation. The validation is not important as such, but I want to understand the PropertyInfo class better.
2 Answers
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Is there a difference between “==” and “is”?
...> b == a
True
# Make a new copy of list `a` via the slice operator,
# and assign it to variable `b`
>>> b = a[:]
>>> b is a
False
>>> b == a
True
In your case, the second test only works because Python caches small integer objects, which is an implementation detail...
How to set timer in android?
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ok since this isn't cleared up yet there are 3 simple ways to handle this.
Below is an example showing all 3 and at the bottom is an example showing just the method I believe is preferable. Also remember to clean up your tasks in onPause, saving state if necessary.
import java.util.T...