20170924习题

 

ex.32
#循环和列表

the_count = [1,2,3,4,5]
fruits = ['apples','oranges','pears','apricots']
change = [1,'pennies',2,'dimes',3,'quarters']

#this first kind of for-loop goes through a list.

for number in the_count:
    print ('this is count %d' %number)

#same as above
for fruit in fruits:
    print('a fruit of type %r' %fruit)

#also we can go through mixed list too.
#notice we have to use %r since we don't know what's in it.

for i in change:
    print('i got %r' %i)

#we can also built lists,first start with an empty one.
elements = []

#then use the range function to do 0 to 5 counts.
for i in range (0,6):
    print('adding %d to the list.' %i)
    #append is a function that lists understand.
    elements.append(i)

#now we can print them out too.
for i in elements:
    print('elements was %d' %i)
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dir（list）

['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '_
_gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__'
, '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'co
unt', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

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dir(range)

['__bool__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__has
h__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '_
_setattr__', '__sizeof__', '__str__', '__subclasshook__', 'count', 'index', 'start', 'step', 'stop']

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