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How do I perform the SQL Join equivalent in MongoDB?
...rect. The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
{
from: <collection to join>,
localField: <...
How to Select Every Row Where Column Value is NOT Distinct
I need to run a select statement that returns all rows where the value of a column is not distinct (e.g. EmailAddress).
7 A...
how to debug the js in jsfiddle
...ever using chrome dev tools. Press ctrl+shift+F and you can search through all the files in the source.
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Team Build Error: The Path … is already mapped to workspace
...ity TF - Team Foundation Version Control Tool (tf).
You can get a list of all workspaces by bringing up a Visual Studio Command Prompt then changing to your workspace folder and issuing the following commands:
C:\YourWorkspaceFolder>tf workspaces /owner:*
You should see your problem workspace...
Cast a Double Variable to Decimal
... No because it will throw an OverflowException double vol_y = (double)Decimal.MaxValue + 10E+28D; Console.WriteLine("Convert.ToDecimal(vol_y) = " + Convert.ToDecimal(vol_y));
– ToXinE
Dec 1 '14 at 15:23
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How do I convert a Ruby class name to a underscore-delimited symbol?
...ow can I programmatically turn a class name, FooBar , into a symbol, :foo_bar ? e.g. something like this, but that handles camel case properly?
...
Running unittest with typical test directory structure
...on -m unittest test.test_antigravity.GravityTestCase.test_method
Running all tests:
You can also use test discovery which will discover and run all the tests for you, they must be modules or packages named test*.py (can be changed with the -p, --pattern flag):
$ cd new_project
$ python -m unitte...
Why is reading lines from stdin much slower in C++ than Python?
...tl;dr: Because of different default settings in C++ requiring more system calls.
By default, cin is synchronized with stdio, which causes it to avoid any input buffering. If you add this to the top of your main, you should see much better performance:
std::ios_base::sync_with_stdio(false);
Normall...
Match whitespace but not newlines
...ghteen horizontal ones which match \h. \s matches twenty-three characters
All whitespace characters are either vertical or horizontal with no overlap, but they are not proper subsets because \h also matches U+00A0 NO-BREAK SPACE, and \v also matches U+0085 NEXT LINE, neither of which are matched by...
class method generates “TypeError: … got multiple values for keyword argument …”
...de:
myfoo.foodo("something")
print
print myfoo
You'll output like:
<__main__.foo object at 0x321c290>
a thong is something
<__main__.foo object at 0x321c290>
You can see that 'thing' has been assigned a reference to the instance 'myfoo' of the class 'foo'. This section of the docs...