大约有 40,000 项符合查询结果（耗时：0.0484秒） [XML]
How to print instances of a class using print()?
...
>>> class Test:
... def __repr__(self):
... return "Test()"
... def __str__(self):
... return "member of Test"
...
>>> t = Test()
>>> t
Test()
>>> print(t)
member of Test
The __str__ method is what h...
Python __str__ and lists
...
Calling string on a python list calls the __repr__ method on each element inside. For some items, __str__ and __repr__ are the same. If you want that behavior, do:
def __str__(self):
...
def __repr__(self):
return self.__str__()
...
Case objects vs Enumerations in Scala
...
One big difference is that Enumerations come with support for instantiating them from some name String. For example:
object Currency extends Enumeration {
val GBP = Value("GBP")
val EUR = Value("EUR") //etc.
}
Then you can do:
val ccy = Currency.withName("E...
iPhone UITextField - Change placeholder text color
... 0x11561d90> valueForUndefinedKey:]: this class is not key value coding-compliant for the key _field.
– i_am_jorf
Apr 9 '14 at 19:27
|
sh...
Relative imports in Python 2.7
...
Naming
When a file is loaded, it is given a name (which is stored in its __name__ attribute). If it was loaded as the top-level script, its name is __main__. If it was loaded as a module, its name is the filename, preceded by the names of any packages/subpackages of which it is a part, separated...
Inverse dictionary lookup in Python
...s slow as yours, because it creates a list from the dict twice.
key = dict_obj.keys()[dict_obj.values().index(value)]
Or if you prefer brevity over readability you can save one more character with
key = list(dict_obj)[dict_obj.values().index(value)]
And if you prefer efficiency, @PaulMcGuire's...
Understanding the map function
...
map isn't particularly pythonic. I would recommend using list comprehensions instead:
map(f, iterable)
is basically equivalent to:
[f(x) for x in iterable]
map on its own can't do a Cartesian product, because the length of its output list is always the same as i...
'Java' is not recognized as an internal or external command
...g, I received the error "java is not recognized as an internal or external command, operable program or batch file.".
14 A...
Continuous Integration for Ruby on Rails? [closed]
...nal Answer
Drone.io
I just setup our main Ruby on Rails application with http://drone.io/. Was a piece of cake and it's got a great interface. I'd say worth checking out if you're looking for a simple, hosted solution.
sha...
How to invoke the super constructor in Python?
...on-3.x the process has been simplified:
Python-2.x
class A(object):
def __init__(self):
print "world"
class B(A):
def __init__(self):
print "hello"
super(B, self).__init__()
Python-3.x
class A(object):
def __init__(self):
print("world")
class B(A):
def __init__(self):
print...