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What exactly does an #if 0 … #endif block do?
...entire thing. And the #if 0s will nest with each other, like so:
#if 0
pre_foo();
#if 0
foo();
bar(x, y); /* x must not be NULL */
baz();
#endif
quux();
#endif
Although of course this can get a bit confusing and become a maintenance headache if not commented properly.
...
How to re import an updated package while in Python Interpreter? [duplicate]
.... When targeting 3 or later, either reference the appropriate module when calling reload or import it.
Takeaway:
Python3 >= 3.4: importlib.reload(packagename)
Python3 < 3.4: imp.reload(packagename)
Python2: continue below
Use the reload builtin function:
https://docs.python.org/2/libr...
Unique fields that allow nulls in Django
...pty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms.ModelForm):
class Meta:
model = Foo
def clean_bar(self):
return self.cleaned_data['bar'] or None
class FooAdmin(admin.ModelAdmin...
Finding the Eclipse Version Number
I have posted how to find it in Eclipse Gallileo, but if anyone has information on older versions feel free to post it below.
...
How to rename a single column in a data.frame?
...r.name'
This code pretty much does the following:
names(df) looks into all the names in the df
[names(df) == old.var.name] extracts the variable name you want to check
<- 'new.var.name' assigns the new variable name.
...
How to install a specific version of a ruby gem?
Using the command-line gem tool, how can I install a specific version of a gem?
6 Answers
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What does ':' (colon) do in JavaScript?
...
var o = {
r: 'some value',
t: 'some other value'
};
is functionally equivalent to
var o = new Object();
o.r = 'some value';
o.t = 'some other value';
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...
Is it safe to resolve a promise multiple times?
... rejected), that is it for a defered object - it is done.
If you should call then(...) on it's promise again, you should immediately get the (first) resolved/rejected result.
Additional calls to resolve() will not (should not?) have any effect. Not sure what happens if you attempt to reject a de...
What is an application binary interface (ABI)?
...but the API does not, then the old and new library versions are sometimes called "source compatible". This implies that while a program compiled for one library version will not work with the other, source code written for one will work for the other if re-compiled.
For this reason, developers ten...
What is Scala's yield?
...I use yield instead of map? This map code is equivalent val res = args.map(_.toUpperCase) , right?
– Geo
Jun 27 '09 at 12:23
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