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Why does ++[[]][+[]]+[+[]] return the string “10”?
...array ([]). Due to references it's wrong to say [[]][0] === [], but let's call the inner array A to avoid the wrong notation.
++ before its operand means “increment by one and return the incremented result”. So ++[[]][0] is equivalent to Number(A) + 1 (or +A + 1).
Again, we can simplify the me...
Assigning default values to shell variables with a single command in bash
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Very close to what you posted, actually:
FOO=${VARIABLE:-default} # If variable not set or null, use default.
Or, which will assign default to VARIABLE as well:
FOO=${VARIABLE:=default} # If variable not set or null, set it to default.
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Staging Deleted files
Say I have a file in my git repository called foo .
9 Answers
9
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What is the use case of noop [:] in bash?
... to do.
while keep_waiting; do
: # busy-wait
done
The : builtin dates all the way back to the Thompson shell, it was present in Unix v6. : was a label indicator for the Thompson shell's goto statement. The label could be any text, so : doubled up as a comment indicator (if there is no goto comm...
When should you use a class vs a struct in C++?
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A struct with no modifiers or methods is called a POD struct, which exists as a backwards compatible interface with C libraries as it is (supposedly) guaranteed to be laid out as though it were a C struct. Apart from this one exception though, the only difference is ...
Django REST Framework: adding additional field to ModelSerializer
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I think SerializerMethodField is what you're looking for:
class FooSerializer(serializers.ModelSerializer):
my_field = serializers.SerializerMethodField('is_named_bar')
def is_named_bar(self, foo):
return foo.name == "bar"
class Meta:
model = Foo
fields = ('id', 'na...
How to quickly clear a JavaScript Object?
...object).
In this example, I believe setting the length to 0 still leaves all of the elements for garbage collection.
You could add this to Object.prototype if it's something you'd frequently use. Yes it's linear in complexity, but anything that doesn't do garbage collection later will be.
This is ...
When vectors are allocated, do they use memory on the heap or the stack?
Are all of the following statements true?
5 Answers
5
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Return a `struct` from a function in C
... from a function, to which I replied: "No! You'd return pointers to dynamically malloc ed struct s instead."
9 Answers
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PostgreSQL - how to quickly drop a user with existing privileges
... experimenting. Is there any way to drop the user without having to revoke all his rights manually first, or revoke all the grants a user has?
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