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Why dict.get(key) instead of dict[key]?
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It allows you to provide a default value if the key is missing:
dictionary.get("bogus", default_value)
returns default_value (whatever you choose it to be), whereas
dictionary["bogus"]
would raise a KeyError.
If omitted...
Set Django IntegerField by choices=… name
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Really like the Encapsulation section on the blog.
– Nathan Keller
Mar 3 '13 at 21:57
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Does Python have an ordered set?
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I'm pretty sure you're not allowed to have two methods both called union in the same class. The last one will "win" and the first one will fail to exist at runtime. This is because OrderedSet.union (no parens) has to refer to a single object.
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python generator “send” function purpose?
...t's useful, one of the best use cases I've seen is Twisted's @defer.inlineCallbacks. Essentially it allows you to write a function like this:
@defer.inlineCallbacks
def doStuff():
result = yield takesTwoSeconds()
nextResult = yield takesTenSeconds(result * 10)
defer.returnValue(nextResu...
6个变态的C语言Hello World程序 - 创意 - 清泛网 - 专注C/C++及内核技术
...要动用C++的编译器g++才能编程通过。
hello1.c
#define _________ }
#define ________ putchar
#define _______ main
#define _(a) ________(a);
#define ______ _______(){
#define __ ______ _(0x48)_(0x65)_(0x6C)_(0x6C)
#define ___ _(0x6F)_(0x2C)_(0x20)_(0x77)_(0x6F)
#define ____ _...
Is there a Python equivalent of the C# null-coalescing operator?
In C# there's a null-coalescing operator (written as ?? ) that allows for easy (short) null checking during assignment:
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How do I avoid capturing self in blocks when implementing an API?
...ied inside the block (we're not doing that) but also they are not automatically retained when the block is retained (unless you are using ARC). If you do this, you must be sure that nothing else is going to try to execute the block after the MyDataProcessor instance is released. (Given the structure...
Standardize data columns in R
I have a dataset called spam which contains 58 columns and approximately 3500 rows of data related to spam messages.
15 ...
What do all of Scala's symbolic operators mean?
...se of teaching, into four categories:
Keywords/reserved symbols
Automatically imported methods
Common methods
Syntactic sugars/composition
It is fortunate, then, that most categories are represented in the question:
-> // Automatically imported method
||= // Syntactic sugar
++= // Syn...
Underscore: sortBy() based on multiple attributes
... said, that's pretty hacky. To do this properly you'd probably want to actually use the core JavaScript sort method:
patients.sort(function(x, y) {
var roomX = x[0].roomNumber;
var roomY = y[0].roomNumber;
if (roomX !== roomY) {
return compare(roomX, roomY);
}
return compare(x[0].name...