我希望能够以字符串的形式获取变量的名称,但我不知道Python是否有那么多的自省功能。喜欢的东西:

>>> print(my_var.__name__)
'my_var'

我想这样做是因为我有一堆变量,我想把它们转换成一个字典,比如:

bar = True
foo = False
>>> my_dict = dict(bar=bar, foo=foo)
>>> print my_dict 
{'foo': False, 'bar': True}

但我想要更自动的。

Python有locals()和vars(),所以我猜有一种方法。


当前回答

这在Python中是不可能的,因为Python真的没有“变量”。Python有名称,同一个对象可以有多个名称。

其他回答

大多数对象没有__name__属性。(类、函数和模块可以;还有其他内置类型吗?)

除了print("my_var"),你还期望print(my_var.__name__)有什么?你能直接使用字符串吗?

你可以"slice" a dict:

def dict_slice(D, keys, default=None):
  return dict((k, D.get(k, default)) for k in keys)

print dict_slice(locals(), ["foo", "bar"])
# or use set literal syntax if you have a recent enough version:
print dict_slice(locals(), {"foo", "bar"})

另外:

throw = object()  # sentinel
def dict_slice(D, keys, default=throw):
  def get(k):
    v = D.get(k, throw)
    if v is not throw:
      return v
    if default is throw:
      raise KeyError(k)
    return default
  return dict((k, get(k)) for k in keys)

I was working on a similar problem. @S.Lott said "If you have the list of variables, what's the point of "discovering" their names?" And my answer is just to see if it could be done and if for some reason you want to sort your variables by type into lists. So anyways, in my research I came came across this thread and my solution is a bit expanded and is based on @rlotun solution. One other thing, @unutbu said, "This idea has merit, but note that if two variable names reference the same value (e.g. True), then an unintended variable name might be returned." In this exercise that was true so I dealt with it by using a list comprehension similar to this for each possibility: isClass = [i for i in isClass if i != 'item']. Without it "item" would show up in each list.

__metaclass__ = type

from types import *

class Class_1: pass
class Class_2: pass
list_1 = [1, 2, 3]
list_2 = ['dog', 'cat', 'bird']
tuple_1 = ('one', 'two', 'three')
tuple_2 = (1000, 2000, 3000)
dict_1 = {'one': 1, 'two': 2, 'three': 3}
dict_2 = {'dog': 'collie', 'cat': 'calico', 'bird': 'robin'}
x = 23
y = 29
pie = 3.14159
eee = 2.71828
house = 'single story'
cabin = 'cozy'

isClass = []; isList = []; isTuple = []; isDict = []; isInt = []; isFloat = []; isString = []; other = []

mixedDataTypes = [Class_1, list_1, tuple_1, dict_1, x, pie, house, Class_2, list_2, tuple_2, dict_2, y, eee, cabin]

print '\nMIXED_DATA_TYPES total count:', len(mixedDataTypes)

for item in mixedDataTypes:
    try:
        # if isinstance(item, ClassType): # use this for old class types (before 3.0)
        if isinstance(item, type):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isClass.append(mapping_as_str)
            isClass = [i for i in isClass if i != 'item']

        elif isinstance(item, ListType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isList.append(mapping_as_str)
            isList = [i for i in isList if i != 'item']

        elif isinstance(item, TupleType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isTuple.append(mapping_as_str)
            isTuple = [i for i in isTuple if i != 'item']

        elif isinstance(item, DictType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isDict.append(mapping_as_str)
            isDict = [i for i in isDict if i != 'item']

        elif isinstance(item, IntType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isInt.append(mapping_as_str)
            isInt = [i for i in isInt if i != 'item']

        elif isinstance(item, FloatType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isFloat.append(mapping_as_str)
            isFloat = [i for i in isFloat if i != 'item']

        elif isinstance(item, StringType):
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    isString.append(mapping_as_str)
            isString = [i for i in isString if i != 'item']

        else:
            for k, v in list(locals().iteritems()):
                if v is item:
                    mapping_as_str = k
                    other.append(mapping_as_str)
            other = [i for i in other if i != 'item']

    except (TypeError, AttributeError), e:
        print e

print '\n isClass:', len(isClass), isClass
print '  isList:', len(isList), isList
print ' isTuple:', len(isTuple), isTuple
print '  isDict:', len(isDict), isDict
print '   isInt:', len(isInt), isInt
print ' isFloat:', len(isFloat), isFloat
print 'isString:', len(isString), isString
print '   other:', len(other), other

# my output and the output I wanted
'''
MIXED_DATA_TYPES total count: 14

 isClass: 2 ['Class_1', 'Class_2']
  isList: 2 ['list_1', 'list_2']
 isTuple: 2 ['tuple_1', 'tuple_2']
  isDict: 2 ['dict_1', 'dict_2']
   isInt: 2 ['x', 'y']
 isFloat: 2 ['pie', 'eee']
isString: 2 ['house', 'cabin']
   other: 0 []
'''

我写了包巫术健壮地做这种魔法。你可以这样写:

from sorcery import dict_of

my_dict = dict_of(foo, bar)
import re
import traceback

pattren = re.compile(r'[\W+\w+]*get_variable_name\((\w+)\)')
def get_variable_name(x):
    return pattren.match( traceback.extract_stack(limit=2)[0][3]) .group(1)

a = 1
b = a
c = b
print get_variable_name(a)
print get_variable_name(b)
print get_variable_name(c)

在python 2.7及更新版本中,还有字典理解,这使得它更短一些。如果可能的话,我会使用getattr代替eval (eval是邪恶的),就像在顶部的答案。Self可以是任何有你正在看的上下文的对象。它可以是一个对象或locals=locals()等。

{name: getattr(self, name) for name in ['some', 'vars', 'here]}