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SQL Joins Vs SQL Subqueries (Performance)?
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I would EXPECT the first query to be quicker, mainly because you have an equivalence and an explicit JOIN. In my experience IN is a very slow operator, since SQL normally evaluates it as a series of WHERE clauses separated by "OR" (WH...
MySQL INNER JOIN select only one row from second table
I have a users table and a payments table, for each user, those of which have payments, may have multiple associated payments in the payments table. I would like to select all users who have payments, but only select their latest payment. I'm trying this SQL but i've never tried nested SQL sta...
Ruby class instance variable vs. class variable
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Instance variable on a class:
class Parent
@things = []
def self.things
@things
end
def things
self.class.things
end
end
class Child < Parent
@things = []
end
Parent.things << :car
Child.things << :doll
mom = Parent.new
dad...
Dynamically update values of a chartjs chart
...created an basic bar chart using chartjs and it works fine. Now I want to update the values on a time based interval. My problem is that after I created the chart, I do not know how to update its values correctly...
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p vs puts in Ruby
Is there any difference between p and puts in Ruby?
7 Answers
7
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How to remove all callbacks from a Handler?
...was called by the main Activity . This Handler is used by sub-classes to postDelay some Runnables, and I can't manage them. Now, in the onStop event, I need to remove them before finishing the Activity (somehow I called finish() , but it still call again and again). Is there anyway to remove a...
How do I calculate percentiles with python/numpy?
Is there a convenient way to calculate percentiles for a sequence or single-dimensional numpy array?
11 Answers
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Twitter bootstrap float div right
What is the proper way in bootstrap to float a div to the right? I thought pull-right was the recommend way, but it is not working.
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Unicode equivalents for \w and \b in Java regular expressions?
Many modern regex implementations interpret the \w character class shorthand as "any letter, digit, or connecting punctuation" (usually: underscore). That way, a regex like \w+ matches words like hello , élève , GOÄ_432 or gefräßig .
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HSL to RGB color conversion
I am looking for a JavaScript / PHP algorithm to convert between HSL color to RGB.
19 Answers
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