序列、元组、列表、字典

By minitia, on 九月 22nd, 2009, Category: Python

# 序列：在 python 里，元组，列表，字符串都称作序列，都可以进行切片操作.
# 元组（）：一组不可修改的元素的集合
# 列表[]: 一组可以任意修改的元素的集合
# 字典{}：一组具有索引的可变的元素的集合

#元组（）：一组不可修改的元素的集合
##########################################
#使用range()循环遍历
tuple = (("apple", "banana"),("grape", "orange"),("watermelon",),("grapefruit",))
for i in range(len(tuple)):
    print "tuple[%d] :" % i, "" ,
    for j in range(len(tuple[i])):
        print tuple[i][j], "" ,
    print

# 列表[]: 一组可以任意修改的元素的集合
##########################################
lst = ['a', 'b', 'c', 'd']; print lst
lst.append("e"); print lst
lst.insert(1, "f"); print lst
lst.remove("b"); print lst
print "弹出的元素：", list.pop()
lst.index(’c'); print lst
lst.sort(); print lst # 排序
lst.reverse(); print lst # 反转

lst1=['aa', 'bb', 'cc', 'd', 'e']
lst2=['a', 'b', 'c', 'd', 'e']
lst3=[i for i in lst1 if i not in lst2] # 合并
lst4=lst1 + lst2
lst2 = lst2 + ['hello']
lst2+ = ['world']

#使用函数sorted排序,返回一个新的列表，不改变原列表的顺序
list = ["banana", "apple", "orange", "grape"]
for li in sorted(set(list)):
print li, "" ,

#堆栈的实现（先进后出）
list = ["apple", "banana", "grape"]
list.append("orange")
print list
print "弹出的元素：", list.pop()
print list

#队列的实现（先进先出）
list = ["apple", "banana", "grape"]
list.append("orange")
print list
print "弹出的元素：", list.pop(0)
print list

# 字典{}：一组具有索引的可变的元素的集合
##########################################
#使用字母作为索引
dict = {"a" : "apple", "b" : "banana", "g" : "grape", "o" : "orange"}
print dict # 排列有字典内部结构排序，不一定与上面顺序相同
print dict["a"]

#使用数字作为索引
dict = {1 : "apple", 2 : "banana", 3 : "grape", 4 : "orange"}
print dict
print dict[2]

#使用元组作为索引
dict = {}
dict[("a","p","p","l","e")] = "apple"
dict[("b","a","n","a","n","a")] = "banana"
print dict
print dict[("a","p","p","l","e")]

#字典的添加、删除、更新
dict = {1 : "apple", 2 : "banana", 3 : "grape", 4 : "orange"}
del dict[2]
dict[2] = ‘zhaohang’
dict[2] = ‘hello’
print dict.pop(4)
dict.clear()
print dict
print dict[2]

#字典的遍历
dict = {"a" : "apple", "b" : "banana", "g" : "grape", "o" : "orange"}
for k in dict:
print "dict[%s] =" % k,dict[k]

#字典items()的使用
dict = {"a" : "apple", "b" : "banana", "c" : "grape", "d" : "orange"}
print dict.keys()
print dict.values()
print dict.items()

#调用items()实现字典的遍历
dict = {"a" : "apple", "b" : "banana", "g" : "grape", "o" : "orange"}
for (k, v) in dict.items():
print "dict[%s] =" % k, v

#使用列表、字典作为字典的值
dict = {"a" : ("apple",), "bo" : {"b" : "banana", "o" : "orange"}, "g" : ["grape","grapefruit"]}

# 字典的合并更新：
dict = {"a" : "apple", "b" : "banana"}
dict2 = {"c" : "grape", "d" : "orange"}
dict.update(dict2)

同：
D = {"key1" : "value1", "key2" : "value2"}
E = {"key3" : "value3", "key4" : "value4"}
for k in E:
D[k] = E[k]

#调用sorted()排序
dict = {"a" : "apple", "b" : "grape", "c" : "orange", "d" : "banana"}
print sorted(dict.items(), key=lambda d: d[0]) #按照key排序
print sorted(dict.items(), key=lambda d: d[1]) #按照value排序

#字典的浅拷贝
dict = {"a" : "apple", "b" : "grape"}
dict2 = {"c" : "orange", "d" : "banana"}
dict2 = dict.copy()
print dict2

# 系统模块查询
import sys
print sys.modules.keys()
print sys.modules.values()
pritn sys.modules.items()
print sys.modules["os"]

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