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What does !! mean in ruby?
...pying from Matt Van Horn's answer with slight modifications:
1 ^ true
TypeError: can't convert true into Integer
!!1 ^ !!true
=> false
I used it to ensure two variables were either both nil, or both not nil.
raise "Inconsistency" if !!a ^ !!b
...
What's the difference between & and && in MATLAB?
...ntees a condition without which the second expression may cause a run-time error. e.g. d != 0 && 1/d vs d !=0 & 1/d - the first guarantees no division by zero, the second doesn't.
– Fraser
Nov 14 '16 at 17:06
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Cannot install Lxml on Mac os x 10.9
...e:
brew unlink libxml2
brew unlink libxslt
If you are having permission errors with Homebrew, especially on El Capitan, this is a helpful document. In essence, regardless of OS X version, try running:
sudo chown -R $(whoami):admin /usr/local
...
How to add leading zeros for for-loop in shell? [duplicate]
...
Use the following syntax:
$ for i in {01..05}; do echo "$i"; done
01
02
03
04
05
Disclaimer: Leading zeros only work in >=bash-4.
If you want to use printf, nothing prevents you from putting its result in a variable for further use:
$ foo=$(printf "%02d" 5)
$ ech...
Does Python have “private” variables in classes?
...t will fail:
>>>x = A()
>>>x.__var # this will return error: "A has no attribute __var"
>>>x.printVar() # this gives back 123
But you can easily get away with this:
>>>x.__dict__ # this will show everything that is contained in object x
# w...
How to customize a Spinner in Android
...height value to "?attr/dropdownListPreferredItemHeight" or you will get an error: "Error: Attribute is not public"
– Loenix
Jun 14 '16 at 6:05
9
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How to speed up insertion performance in PostgreSQL
...here's no practical limit AFAIK, but batching will let you recover from an error by marking the start of each batch in your input data. Again, you seem to be doing this already.
Use synchronous_commit=off and a huge commit_delay to reduce fsync() costs. This won't help much if you've batched your wo...
Transfer git repositories from GitLab to GitHub - can we, how to and pitfalls (if any)?
...ssue with the https URL of the GitHub repo:
The requested URL returned an error: 403
All you need to do is to enter your GitHub password, but the OP suggests:
Then you might need to push it the ssh way. You can read more on how to do it here.
See "Pushing to Git returning Error Code 403 fat...
Dynamically access object property using variable
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careful with this: javascript compilers will error here since they dont rename strings but they do rename object properties
– chacham15
Dec 6 '11 at 8:40
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Celery Received unregistered task of type (run example)
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+1 for --loglevel=DEBUG, there was a syntax error in my task.
– Jacob Valenta
Dec 11 '13 at 19:51
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