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Unable to create/open lock file: /data/mongod.lock errno:13 Permission denied
...irectory.
Then I ran sudo service mongodb start and waited about a minute. If you try to connect to 27017 immediately you won't be able to.
After a minute check /data/db (EBS volume) and mongo should have placed a journal, mongod.lock, local.ns, local.0, etc. If not try sudo service mongodb restart ...
Remove non-ascii character in string
..., when expressing unicode for a regular expression, the characters are specified with the escape sequence \u{xxxx} but also the flag 'u' must present; note the regex has flags 'gu'.
I called this a "positive assertion of removal" in the sense that a "positive" assertion expresses which characters t...
Is the C# static constructor thread safe?
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Note that if your singleton object is immutable, using a mutex or any synchronization mechanism is an overkill and should not be used. Also, I find the above sample implementation extremely brittle :-). All code using Singleton.Acquir...
How to install pip for Python 3 on Mac OS X?
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I had to go through this process myself and chose a different way that I think is better in the long run.
I installed homebrew
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
then:
brew doctor
The last step gives you some warnin...
memcpy() vs memmove()
I am trying to understand the difference between memcpy() and memmove() , and I have read the text that memcpy() doesn't take care of the overlapping source and destination whereas memmove() does.
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Func vs. Action vs. Predicate [duplicate]
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The difference between Func and Action is simply whether you want the delegate to return a value (use Func) or not (use Action).
Func is probably most commonly used in LINQ - for example in projections:
list.Select(x => x.So...
How to compare two Dates without the time portion?
...();
return firstDate.compareTo(secondDate);
EDIT: As noted in comments, if you use DateTimeComparator.getDateOnlyInstance() it's even simpler :)
// TODO: consider extracting the comparator to a field.
return DateTimeComparator.getDateOnlyInstance().compare(first, second);
("Use Joda Time" is t...
Where to put include statements, header or source?
Should I put the includes in the header file or the source file? If the header file contains the include statements, then if I include that header file in my source, then will my source file have all of the included files that were in my header? Or should I just include them in my source file only?
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Count the number occurrences of a character in a string
...nswers said, using the string method count() is probably the simplest, but if you're doing this frequently, check out collections.Counter:
from collections import Counter
my_str = "Mary had a little lamb"
counter = Counter(my_str)
print counter['a']
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Twitter bootstrap dropdown goes outside the screen
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This answer does not actually fix the problem if user is using some smaller screen device -- it is going out of the left side in stead of right side (in fact that you just change the pull-left to the pull-right).
– Anonymous
Nov 9 '...