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Python “raise from” usage
...rinted.
See the raise statement documenation:
The from clause is used for exception chaining: if given, the second expression must be another exception class or instance, which will then be attached to the raised exception as the __cause__ attribute (which is writable). If the raised exception ...
How to get a function name as a string?
...unction.__name__
Using __name__ is the preferred method as it applies uniformly. Unlike func_name, it works on built-in functions as well:
>>> import time
>>> time.time.func_name
Traceback (most recent call last):
File "<stdin>", line 1, in ?
AttributeError: 'builtin_fun...
In which situations do we need to write the __autoreleasing ownership qualifier under ARC?
...declaration means __strong, implicitly:
NSError * e = nil;
Will be transformed to:
NSError * __strong error = nil;
When you call your save method:
- ( BOOL )save: ( NSError * __autoreleasing * );
The compiler will then have to create a temporary variable, set at __autoreleasing. So:
NSErro...
Why is Python 3.x's super() magic?
...current implementation instead. He anticipated that using a different name for super() could be a problem:
My patch uses an intermediate solution: it assumes you need __class__
whenever you use a variable named 'super'. Thus, if you (globally)
rename super to supper and use supper but not su...
method of iterating over sqlalchemy model's defined columns?
... iterate over the list of columns defined in a SQLAlchemy model. I want it for writing some serialization and copy methods to a couple of models. I can't just iterate over the obj.__dict__ since it contains a lot of SA specific items.
...
What's the difference between globals(), locals(), and vars()?
...: '__main__',
}
So far, everything I've said about locals() is also true for vars()... here's the difference: vars() accepts a single object as its argument, and if you give it an object it returns the __dict__ of that object. For a typical object, its __dict__ is where most of its attribute dat...
Stop pip from failing on single package when installing with requirements.txt
...
for mac: cat requirements.txt | xargs -n 1 pip install
– Walty Yeung
Sep 4 '16 at 1:32
5
...
Should I use a class or dictionary?
...ter want to add some code? Where would your __init__ code go?
Classes are for bundling related data (and usually code).
Dictionaries are for storing key-value relationships, where usually the keys are all of the same type, and all the values are also of one type. Occasionally they can be useful fo...
Lua简明教程 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...外，条件表达式中的与或非为分是：and, or, not关键字。
for 循环
从1加到100
1
2
3
4
sum = 0
for i = 1, 100 do
sum = sum + i
end
从1到100的奇数和
1
2
3
4
sum = 0
for ...
Best practices for circular shift (rotate) operations in C++
... are already available in C++.
However, I couldn't find out how I could perform circular shift or rotate operations.
16 Ans...