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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: <...
Get string between two strings in a string
...ng on how robust/flexible you want your implementation to be, this can actually be a bit tricky. Here's the implementation I use:
public static class StringExtensions {
/// <summary>
/// takes a substring between two anchor strings (or the end of the string if that anchor is null)
...
How to list of all the tables defined for the database when using active record?
How do I get a list of all the tables defined for the database when using active record?
5 Answers
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Elasticsearch query to return all records
I have a small database in Elasticsearch and for testing purposes would like to pull all records back. I am attempting to use a URL of the form...
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How does a debugger work?
... will look up the process ID, and initiate the debug session via a system call; under Windows this would be DebugActiveProcess.
Once attached, the debugger will enter an event loop much like for any UI, but instead of events coming from the windowing system, the OS will generate events based on wha...
Python read-only property
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Generally, Python programs should be written with the assumption that all users are consenting adults, and thus are responsible for using things correctly themselves. However, in the rare instance where it just does not make sens...
Why does ReSharper tell me “implicitly captured closure”?
... use.
The compiler generates a class for both lambda expressions and puts all variables in that class which are used in the lambda expressions.
So in my example g and i are held in the same class for execution of my delegates. If g is a heavy object with a lot of resources left behind, the garbage...
You have already activated rake 0.9.0, but your Gemfile requires rake 0.8.7
... you'll need to tell bundle to update the rake version it's using for your app:
bundle update rake
It'll update your Gemfile.lock for you.
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Importing from builtin library when module with same name exists
Situation:
- There is a module in my project_folder called calendar
- I would like to use the built-in Calendar class from the Python libraries
- When I use from calendar import Calendar it complains because it's trying to load from my module.
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Finding what methods a Python object has
Given a Python object of any kind, is there an easy way to get the list of all methods that this object has?
19 Answers
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