大约有 40,000 项符合查询结果（耗时：0.0470秒） [XML]
How to add property to a class dynamically?
...ing on. Better late than never.
You can add a property to a class dynamically. But that's the catch: you have to add it to the class.
>>> class Foo(object):
... pass
...
>>> foo = Foo()
>>> foo.a = 3
>>> Foo.b = property(lambda self: self.a + 1)
>>&...
Saving an Object (Data persistence)
...ics.
cPickle (or _pickle) vs pickle
It's almost always preferable to actually use the cPickle module rather than pickle because the former is written in C and is much faster. There are some subtle differences between them, but in most situations they're equivalent and the C version will provide gr...
What is a clean, pythonic way to have multiple constructors in Python?
...
Actually None is much better for "magic" values:
class Cheese():
def __init__(self, num_holes = None):
if num_holes is None:
...
Now if you want complete freedom of adding more parameters:
class Cheese...
How to get all registered routes in Express?
... web application built using Node.js and Express. Now I would like to list all registered routes with their appropriate methods.
...
How to downgrade or install an older version of Cocoapods
How can I downgrade Cocoapods to an older version, or how can I install an older version of Cocoapods?
6 Answers
...
How update the _id of one MongoDB Document?
I want update an _id field of one document. I know it's not a really good pratice. But with some technical reason, I need update it. If I try to update it I get:
...
How to len(generator()) [duplicate]
...
Generators have no length, they aren't collections after all.
Generators are functions with a internal state (and fancy syntax). You can repeatedly call them to get a sequence of values, so you can use them in loop. But they don't contain any elements, so asking for the length of ...
Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'?,./
...
The regular expression for this is really simple. Just use a character class. The hyphen is a special character in character classes, so it needs to be first:
/[-!$%^&*()_+|~=`{}\[\]:";'<>?,.\/]/
You also need to escape the other regular expressio...
Correct use of Multimapping in Dapper
...ID,
CustomerName.
This makes the spliton: parameter not so useful, especially when you're not sure what order the columns are returned in. Of course you could manually specify columns...but it's 2017 and we just rarely do that anymore for basic object gets.
What we do, and it's worked great fo...
Placeholder in UITextView
...
I made a few minor modifications to bcd's solution to allow for initialization from a Xib file, text wrapping, and to maintain background color. Hopefully it will save others the trouble.
UIPlaceHolderTextView.h:
#import <Foundation/Foundation.h>
IB_DESIGNABLE
@interfac...