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How do I clone a Django model instance object and save it to the database?
...imary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: https://docs.djangoproject.com/en/2.2/topics/db/que...
How does the String class override the + operator?
...emp="x = "+x;
The compiler converts "x = "+x; into a StringBuilder internally and uses .append(int) to "add" the integer to the string.
5.1.11. String Conversion
Any type may be converted to type String by string conversion.
A value x of primitive type T is first converted to a referenc...
Get “Value” property in IGrouping
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The group implements IEnumerable<T> - In the general case, just call foreach over the group. In this case, since you need a List<T>:
list.Add(new DespatchGroup(group.Key, group.ToList());
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Extract subset of key-value pairs from Python dictionary object?
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If you're using Python 3, and you only want keys in the new dict that actually exist in the original one, you can use the fact to view objects implement some set operations:
{k: bigdict[k] for k in bigdict.keys() & {'l', 'm', 'n'}}
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Function to Calculate Median in SQL Server
...that may yield better results. Also, SQL Server releases since then (especially SQL 2012) have introduced new T-SQL features that can be used to calculate medians. SQL Server releases have also improved its query optimizer which may affect perf of various median solutions. Net-net, my original 2009 ...
What should be the values of GOPATH and GOROOT?
I'm trying to install doozer like this:
18 Answers
18
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What is Python buffer type for?
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
Is a statically-typed full Lisp variant possible?
Is a statically-typed full Lisp variant possible? Does it even make sense for something like this to exist? I believe one of a Lisp language's virtues is the simplicity of its definition. Would static typing compromise this core principle?
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Default parameters with C++ constructors [closed]
...ks in their favor.
One thing to watch out for is if you have defaults for all but one parameter, your class can be implicitly converted from that parameter type. Check out this thread for more info.
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Extracting the last n characters from a string in R
... @mdsumner points out. Consider:
x <- c("some text in a string", "I really need to learn how to count")
substrRight(x, 6)
[1] "string" " count"
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