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Mongo: find items that don't have a certain field
...Aug 11 '16 at 18:02
Somnath Muluk
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answered Apr 19 '11 at 16:19
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What is the difference between “ is None ” and “ ==None ”
...ree to implement
comparison any way it chooses, and it
can choose to make comparison against
None mean something (which actually
makes sense; if someone told you to
implement the None object from
scratch, how else would you get it to
compare True against itself?).
Practically-speakin...
Difference between CMAKE_CURRENT_SOURCE_DIR and CMAKE_CURRENT_LIST_DIR
CMAKE_CURRENT_SOURCE_DIR
this is the directory where the currently processed CMakeLists.txt is located in
1 Answer
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Differences between Oracle JDK and OpenJDK
Are there any crucial differences between Oracle and OpenJDK?
11 Answers
11
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Compare integer in bash, unary operator expected
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Your problem arises from the fact that $i has a blank value when your statement fails. Always quote your variables when performing comparisons if there is the slightest chance that one of them may be empty, e.g.:
if [ "$i" -ge 2 ] ; then
...
fi
This is because of how the...
android fragment onRestoreInstanceState
...ted, which receives a bundle with the saved instance state (or null).
Check the source code here.
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C#: Assign same value to multiple variables in single statement
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When using an object property instead of variable, it is interesting to know that the get accessor of the intermediate value is not called. Only the set accessor is invoked for all property accessed in the assignation sequence.
Take for example a class that write to the console everytime the get...
Best practice for Python assert
...gt;> m = MyClass()
>>> m.x = 10
>>> m.x -= 20
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "my.py", line 7, in __set__
raise LessThanZeroException('x is less than zero')
LessThanZeroException: x is less than zero
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How to save a Python interactive session?
I find myself frequently using Python's interpreter to work with databases, files, etc -- basically a lot of manual formatting of semi-structured data. I don't properly save and clean up the useful bits as often as I would like. Is there a way to save my input into the shell (db connections, varia...
How to get a Docker container's IP address from the host
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The --format option of inspect comes to the rescue.
Modern Docker client syntax is:
docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_name_or_id
Old Docker client syntax is:
docker inspect --format '{{ .NetworkSettings.IPAddress }}' container_nam...