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What is a NullReferenceException, and how do I fix it?
.... This means you either set it to null, or you never set it to anything at all.
Like anything else, null gets passed around. If it is null in method "A", it could be that method "B" passed a null to method "A".
null can have different meanings:
Object variables which are uninitialized and hence poi...
Dynamic instantiation from string name of a class in dynamically imported module?
...
You can use getattr
getattr(module, class_name)
to access the class. More complete code:
module = __import__(module_name)
class_ = getattr(module, class_name)
instance = class_()
As mentioned below, we may use importlib
import importlib
module = importlib.imp...
How to create fixed space and flexible space bar button items programmatically?
I want to create UIBarButtonItems programmatically and place these fixed space items between buttons.
7 Answers
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Python append() vs. + operator on lists, why do these give different results?
...quences) by concatenating the element. The append-method however does literally what you ask: append the object on the right-hand side that you give it (the array or any other object), instead of taking its elements.
An alternative
Use extend() if you want to use a function that acts similar to the ...
Role/Purpose of ContextLoaderListener in Spring?
...ates the WebApplicationContext. Otherwise it would need to be created manually.
– sourcedelica
Jul 26 '13 at 15:21
do...
Javascript heredoc
...plicable if you just wanted multi-line strings. However, since you can't really change the symbol that encloses your string, it's not really heredoc.
– Peeyush Kushwaha
Apr 23 '16 at 9:14
...
How to get a reference to current module's attributes in Python
...he way I typically see this done is like this:
import sys
dir(sys.modules[__name__])
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python assert with and without parenthesis
...through IDLE. Because assert is a keyword and not a function, you are actually passing in a tuple as the first argument and leaving off the second argument.
Recall that non-empty tuples evaluate to True, and since the assertion message is optional, you've essentially called assert True when you wr...
How do I convert a Vector of bytes (u8) to a string
...("result: {}", s);
}
The conversion is in-place, and does not require an allocation. You can create a String from the string slice if necessary by calling .to_owned() on the string slice (other options are available).
The library reference for the conversion function:
std::str::from_utf8
...
Export and Import all MySQL databases at one time
I want to keep a backup of all my MySQL databases. I have more than 100 MySQL databases. I want to export all of them at the same time and again import all of them into my MySQL server at one time. How can I do that?
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