我想简单地表达任何类,例如{ property = value }
,是否有自动__repr__
?
答案 0 :(得分:8)
是的,您可以创建一个类“AutoRepr”并让所有其他类扩展它:
>>> class AutoRepr(object):
... def __repr__(self):
... items = ("%s = %r" % (k, v) for k, v in self.__dict__.items())
... return "<%s: {%s}>" % (self.__class__.__name__, ', '.join(items))
...
>>> class AnyOtherClass(AutoRepr):
... def __init__(self):
... self.foo = 'foo'
... self.bar = 'bar'
...
>>> repr(AnyOtherClass())
"<AnyOtherClass: {foo = 'foo', bar = 'bar'}>"
请注意,上述代码不能很好地处理(直接或间接)引用自身的数据结构。作为替代方案,您可以定义适用于任何类型的函数:
>>> def autoRepr(obj):
... try:
... items = ("%s = %r" % (k, v) for k, v in obj.__dict__.items())
... return "<%s: {%s}." % (obj.__class__.__name__, ', '.join(items))
... except AttributeError:
... return repr(obj)
...
>>> class AnyOtherClass(object):
... def __init__(self):
... self.foo = 'foo'
... self.bar = 'bar'
...
>>> autoRepr(AnyOtherClass())
"<AnyOtherClass: {foo = 'foo', bar = 'bar'}>"
>>> autoRepr(7)
'7'
>>> autoRepr(None)
'None'
请注意,由于前面提到的原因,上述函数没有故意递归定义。
答案 1 :(得分:8)
最简单的方法:
def __repr__(self):
return str(self.__dict__)
答案 2 :(得分:3)
你的意思是
__dict__
答案 3 :(得分:3)
好吧,我玩了一些其他答案并得到了一个非常漂亮的解决方案:
class data:
@staticmethod
def repr(obj):
items = []
for prop, value in obj.__dict__.items():
try:
item = "%s = %r" % (prop, value)
assert len(item) < 20
except:
item = "%s: <%s>" % (prop, value.__class__.__name__)
items.append(item)
return "%s(%s)" % (obj.__class__.__name__, ', '.join(items))
def __init__(self, cls):
cls.__repr__ = data.repr
self.cls = cls
def __call__(self, *args, **kwargs):
return self.cls(*args, **kwargs)
您将其用作装饰者:
@data
class PythonBean:
def __init__(self):
self.int = 1
self.list = [5, 6, 7]
self.str = "hello"
self.obj = SomeOtherClass()
开箱即可获得智能__repr__
:
PythonBean(int = 1, obj: <SomeOtherClass>, list = [5, 6, 7], str = 'hello')
这适用于任何递归类,包括树结构。如果您尝试在类self.ref = self
中添加自引用,该函数将尝试(成功)将其处理大约一秒钟。
当然,永远都要关心你的老板 - 我不会喜欢这样的语法糖))
答案 4 :(得分:2)
class MyClass:
def __init__(self, foo: str, bar: int):
self.foo = foo
self.bar = bar
self._baz: bool = True
def __repr__(self):
f"{self.__class__.__name__}({', '.join([f'{k}={v}' for k, v in self.__dict__.items() if not k.startswith('_')])})"
mc = MyClass('a', 99)
print(mc)
# MyClass(foo=a, bar=99)
# ^^^ Note that _baz=True was hidden here
答案 5 :(得分:1)
我使用这个辅助函数为我的类生成 repr 。它很容易在单元测试函数中运行,即
def test_makeRepr(self):
makeRepr(Foo, Foo(), "anOptional space delimitedString ToProvideCustom Fields")
这应该会向控制台输出一些潜在的 repr ,然后您可以将其复制/粘贴到您的班级中。
def makeRepr(classObj, instance = None, customFields = None):
"""Code writing helper function that will generate a __repr__ function that can be copy/pasted into a class definition.
Args:
classObj (class):
instance (class):
customFields (string):
Returns:
None:
Always call the __repr__ function afterwards to ensure expected output.
ie. print(foo)
def __repr__(self):
msg = "<Foo(var1 = {}, var2 = {})>"
attributes = [self.var1, self.var2]
return msg.format(*attributes)
"""
if isinstance(instance, classObj):
className = instance.__class__.__name__
else:
className=classObj.__name__
print('Generating a __repr__ function for: ', className,"\n")
print("\tClass Type: "+classObj.__name__, "has the following fields:")
print("\t"+" ".join(classObj.__dict__.keys()),"\n")
if instance:
print("\tInstance of: "+instance.__class__.__name__, "has the following fields:")
print("\t"+" ".join(instance.__dict__.keys()),"\n")
else:
print('\tInstance of: Instance not provided.\n')
if customFields:
print("\t"+"These fields were provided to makeRepr:")
print("\t"+customFields,"\n")
else:
print("\t"+"These fields were provided to makeRepr: None\n")
print("Edit the list of fields, and rerun makeRepr with the new list if necessary.\n\n")
print("repr with class type:\n")
classResult = buildRepr( classObj.__name__, " ".join(classObj.__dict__.keys()))
print(classResult,"\n\n")
if isinstance(instance, classObj):
instanceResult = buildRepr( instance.__class__.__name__, " ".join(instance.__dict__.keys()))
else:
instanceResult = "\t-----Instance not provided."
print("repr with instance of class:\n")
print(instanceResult,"\n\n")
if customFields:
customResult = buildRepr( classObj.__name__, customFields)
else:
customResult = '\t-----Custom fields not provided'
print("repr with custom fields and class name:\n")
print(customResult,"\n\n")
print('Current __repr__')
print("Class Object: ",classObj)
if instance:
print("Instance: ",instance.__repr__())
else:
print("Instance: ", "None")
def buildRepr(typeName,fields):
funcDefLine = "def __repr__(self):"
msgLineBase = ' msg = "<{typename}({attribute})>"'
attributeListLineBase = ' attributes = [{attributeList}]'
returnLine = ' return msg.format(*attributes)'
x = ['self.' + x for x in fields.split()]
xResult = ", ".join(x)
y = [x + ' = {}' for x in fields.split()]
yResult = ', '.join(y)
msgLine = msgLineBase.format(typename = typeName, attribute = yResult)
attributeListLine = attributeListLineBase.format(attributeList = xResult)
result = "{declaration}\n{message}\n{attributes}\n{returnLine}".format(declaration = funcDefLine,
message = msgLine,
attributes = attributeListLine,
returnLine =returnLine )
return result