python 2-2 如何为元组中的每个元素命名, 提高程序可读性-collections.namedtuple

解决方案:

1.使用下标 定义类似其语言的枚举类型，也就是定义一系列的数值常量

NAME,AGE,SEX,EMAIL=xrange(4)

student=(‘jim’,16,’male’,’weihuap8@126.com’)

print student[EMAIL]

2.使用关键字namedtuple 替代内置的tuple

from collections import namedtuple

Person = namedtuple('Person',['name','age','sex','email'])
person1 = Person("xiaowang",55,1,'xiaowang@126.com')
print person1.email

import collections
dir(collections)
['Callable', 'Container', 'Counter', 'Hashable', 'ItemsView', 'Iterable', 'Iterator', 'KeysView', 'Mapping', 'MappingView', 'MutableMapping', 'MutableSequence', 'MutableSet', 'OrderedDict', 'Sequence', 'Set', 'Sized', 'ValuesView', '__all__', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '_abcoll', '_chain', '_get_ident', '_heapq', '_iskeyword', '_itemgetter', '_repeat', '_starmap', '_sys', 'defaultdict', 'deque', 'namedtuple']
>>>
>>> help(collections.namedtuple)
Help on function namedtuple in module collections:

namedtuple(typename, field_names, verbose=False, rename=False)
Returns a new subclass of tuple with named fields.

>>> Point = namedtuple('Point', 'x y')
>>> Point.__doc__                   # docstring for the new class
'Point(x, y)'
>>> p = Point(11, y=22)             # instantiate with positional args or keywords
>>> p[0] + p[1]                     # indexable like a plain tuple
33
>>> x, y = p                        # unpack like a regular tuple
>>> x, y
(11, 22)
>>> p.x + p.y                       # fields also accessable by name
33
>>> d = p._asdict()                 # convert to a dictionary
>>> d['x']
11
>>> Point(**d)                      # convert from a dictionary
Point(x=11, y=22)
>>> p._replace(x=100)               # _replace() is like str.replace() but targets named fields
Point(x=100, y=22)

def namedtuple(typename, field_names, verbose=False,
rename=False):
"""Returns a new subclass of tuple with named fields.

>>> Point = namedtuple('Point', ['x', 'y'])
>>> Point.__doc__                   # docstring for the new class
'Point(x, y)'
>>> p = Point(11, y=22)             # instantiate with positional
args or keywords
>>> p[0] + p[1]                     # indexable like a plain tuple
33
>>> x, y = p                        # unpack like a regular tuple
>>> x, y
(11, 22)
>>> p.x + p.y                       # fields also accessable by name
33
>>> d = p._asdict()                 # convert to a dictionary
>>> d['x']
11
>>> Point(**d)                      # convert from a dictionary
Point(x=11, y=22)
>>> p._replace(x=100)               # _replace() is like str.replace()
but targets named fields
Point(x=100, y=22)

方案1：

t = range(4)
t2 = xrange(4)
NAME,AGE,SEX,EMAIL = xrange(4)
print NAME,AGE,SEX,EMAIL
person = ('weihuap',23,1,'xxyy@126.com')

print person[NAME]

方案2：

from collections import namedtuple

Person = namedtuple('Person',['name','age','sex','email'])
person1 = Person("xiaowang",55,1,'xiaowang@126.com')
print person1.email
person2 = person1._replace(email="xiaoming333@126.com")
print person1.email
print person2.email

dperson = person1._asdict()
print dperson['email']

dict1 = {'age':185,'email':'xiaoming@126.com','sex':2,'name':'xiaoming'}

tuple1 = Person(**dict1)
print tuple1.name