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Want to find records with no associated records in Rails
...).where( :friends => { :person_id => nil } )
For the hmt it's basically the same thing, you rely on the fact that a person with no friends will also have no contacts:
Person.includes(:contacts).where( :contacts => { :person_id => nil } )
Update
Got a question about has_one in the c...
How do cache lines work?
...hyperthreading is way better than in P4 days (so a prefetch thread is typically a waste). Also, the x86 tag wiki has lots of performance links for that architecture.
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How to calculate date difference in JavaScript?
... 24 hours, and any 'variation' in that due to Daylight Savings Time is actually a switch of timezones. If you don't distinguish between timezones already, trying to figure out a time difference is going to put you in a world of hurt, not least because the DST switchover 'repeats' time. Stay in one t...
Convert String[] to comma separated string in java
...en a bunch of checks. I'm just explaining the concept, not giving the save-all example.
– Nico Huysamen
Jul 8 '11 at 10:27
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Best practices for overriding isEqual: and hash
...ly attributed to Dan Bernstein or Chris Torek. That older algorithm originally floated around on Usenet, and certain attribution is difficult. For example, there is some interesting commentary in this Apache code (search for their names) that references the original source.
Bottom line is, this i...
Eclipse interface icons very small on high resolution screen in Windows 8.1
...rious icons and buttons in the Eclipse (Kepler) interface are very, very small on a laptop with a 3200x1800px screen. The red error decoration that appears to indicate errors on files is difficult to see unless my nose a few cm from the screen.
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How do I create a custom Error in JavaScript?
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I'm still a bit lost in all those prototype things. Why in your example you assign name to this.name and not to NotImplementedError.prototype.name? Can you answer please, it's crucial for my understanding :)
– jayarjo
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Better to 'try' something and catch the exception or test if it's possible first to avoid an excepti
...est option when the index is probably in the list and the IndexError is usually not raised. This way you avoid the need for an extra lookup by if index < len(my_list).
Python encourages the use of exceptions, which you handle is a phrase from Dive Into Python. Your example not only handles the e...
Is proprietary code legally safe on bitbucket or github? [closed]
... yours. However, by setting your pages to be viewed publicly, you agree to allow others to view your Content. By setting your repositories to be viewed publicly, you agree to allow others to view and fork your repositories.
As noted in the BitBucket TOS you linked, BitBucket's parent company simil...
Fetch frame count with ffmpeg
...default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. See the other methods listed below.
ffprobe: Count the number of frames
ffprobe -v error -count_frames -select_streams v:0 -sh...