摘要：列表嵌套列表，相當(dāng)于其他語言中的二維數(shù)組列表的基本操作宮保雞丁宮保雞丁糖醋里脊粉絲蒸蝦魚香肉絲魚香肉絲宮保雞丁糖醋里脊粉絲蒸蝦魚香肉絲宮保雞丁糖醋里脊宮保雞丁糖醋里脊粉絲蒸蝦魚香肉絲魚香肉絲宮保雞丁糖醋里脊粉絲蒸蝦魚香肉絲魚香肉絲宮保雞
列表(list)
>>> type([1,2,3,4,5,6])
>>> type(["hello","worls",1,9])
>>> type(["hello","worls",1,9,True,False])
>>> type([[1,2],[3,4],[True,False]])//嵌套列表，相當(dāng)于其他語言中的二維數(shù)組
列表的基本操作
"宮保雞丁"
>>> ["宮保雞丁","糖醋里脊","粉絲蒸蝦","魚香肉絲"][3]
"魚香肉絲"
>>> ["宮保雞丁","糖醋里脊","粉絲蒸蝦","魚香肉絲"][0:2]
["宮保雞丁", "糖醋里脊"]
>>> ["宮保雞丁","糖醋里脊","粉絲蒸蝦","魚香肉絲"][-1]
"魚香肉絲"
>>> ["宮保雞丁","糖醋里脊","粉絲蒸蝦","魚香肉絲"][-1:]
["魚香肉絲"]
>>> ["宮保雞丁","糖醋里脊","粉絲蒸蝦","魚香肉絲"]+["拍黃瓜","炒豆芽"]
["宮保雞丁", "糖醋里脊", "粉絲蒸蝦", "魚香肉絲", "拍黃瓜", "炒豆芽"]
>>> ["拍黃瓜","炒豆芽"]*["拍黃瓜","炒豆芽"]
Traceback (most recent call last):
File "", line 1, in
["拍黃瓜","炒豆芽"]*["拍黃瓜","炒豆芽"]
TypeError: can"t multiply sequence by non-int of type "list"
>>> ["拍黃瓜","炒豆芽"]*3
["拍黃瓜", "炒豆芽", "拍黃瓜", "炒豆芽", "拍黃瓜", "炒豆芽"]
>>> ["拍黃瓜","炒豆芽"]-["拍黃瓜"]
Traceback (most recent call last):
File "", line 1, in
["拍黃瓜","炒豆芽"]-["拍黃瓜"]
TypeError: unsupported operand type(s) for -: "list" and "list"
元組(tuple)
>>> (1,2,3,4,5)
(1, 2, 3, 4, 5)
>>> (1,"-1",True)
(1, "-1", True)
>>> (1,2,3,4)[0]
1
>>> (1,2,3,4)[0:2]
(1, 2)
>>> (1,2,3)+(4,5,6)
(1, 2, 3, 4, 5, 6)
>>> (1,2,3)*3
(1, 2, 3, 1, 2, 3, 1, 2, 3)
>>> type((1,2,3))
>>> type(1)
>>> type([1,2,3])
>>> type("hello")
>>> type(("hello"))
>>> type((1))//如果括號里只有一個元素，python會默認(rèn)為是要做數(shù)學(xué)運算，等同于type(1)
>>> (1+1)*2
4
>>> (1,2,3)
(1, 2, 3)
>>> (1)
1
>>> (1,)
(1,)
>>> type((1,))
>>> type(())
>>> type([1])
str list tuple都是序列
>>> "hello world"[2]
"l"
>>> [1,2,3][2]
3
>>> (1,2,3)[2]
3
切片
>>> [1,2,3,4,5][0:3]
[1, 2, 3]
>>> [1,2,3,4,5][-1:]
[5]
>>>
>>> "hello world"[0:8:0]
Traceback (most recent call last):
File "", line 1, in
"hello world"[0:8:0]
ValueError: slice step cannot be zero
>>> "hello world"[0:8:1]
"hello wo"
>>> "hello world"[0:8:2]
"hlow"
>>> "hello world"[0:8:3]
"hlw"
>>> "hello world"[0:8:4]
"ho"
>>> "hello world"[0:8:5]
"h "
>>> "hello world"[0:8:6]
"hw"
>>> "hello world"[0:8:7]
判斷一個序列中是否包含某個元素
>>> 3 in [1,2,3,4,5,6]
True
>>> 7 in [1,2,3,4,5,6]
False
>>> 3 not in [1,2,3,4,5,6]
False
序列的其他操作
>>> len([1,2,3,4,5,6])
6
>>> len("hello world")
11
>>> max([1,2,3,4,5,6])
6
>>> min([1,2,3,4,5,6])
1
>>> max("hello world")
"w"
>>> min("hello world")
" "
>>> min("helloworld")
"d"
ASCII碼
>>> ord("w")
119
>>> ord("d")
100
>>> ord(" ")
32
set 集合
集合的特性
>>> type({1,2,3,4,5,6})
>>> {1,2,3,4,5,6}[0] //集合是無序的，沒有像str，list，tuple的架構(gòu)索引,不能切片
Traceback (most recent call last):
File "", line 1, in
{1,2,3,4,5,6}[0]
TypeError: "set" object does not support indexing
>>> {1,2,3,4,5,6}[0:2]
Traceback (most recent call last):
File "", line 1, in
{1,2,3,4,5,6}[0:2]
TypeError: "set" object is not subscriptable
>>> {1,1,2,2,3,3,4,4} //集合的第二個特性：不重復(fù)
{1, 2, 3, 4}
集合的操作
>>> len({1,2,3})
3
>>> len({1,1,1})
1
>>> len({1,2,2})
2
>>> 1 in {1,2,3}
True
>>> 1 not in {1,2,3}
False
>>> {1,2,3,4,5,6} - {3,4} //求兩個集合的差集
{1, 2, 5, 6}
>>> {1,2,3,4,5,6} & {3,4} //交集
{3, 4}
>>> {1,2,3,4,5,6} | {3,4,7} //合集|并集
{1, 2, 3, 4, 5, 6, 7}
//定義一個空的集合set()
>>> type({})
>>> type(set())
>>> len(set())
0
dict 字典
一個字典可以有很多個key和value，字典是一個集合類型，而不是序列
通過key 得到/訪問 value
>>> {"menu1":"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}[0]
Traceback (most recent call last):
File "", line 1, in
{"menu1":"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}[0]
KeyError: 0
>>> {"menu1":"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}["menu1"]
"宮保雞丁"
>>> {"menu1":"宮保雞丁","menu1":"白斬雞","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}["menu1"]
"白斬雞"
>>> {"menu1":"宮保雞丁","menu1":"白斬雞","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}
{"menu1": "白斬雞", "menu2": "糖醋里脊", "menu3": "粉絲蒸蝦", "menu4": "魚香肉絲"}
>>> {1:"宮保雞丁","1":"白斬雞","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"} //key也可以是數(shù)字
{1: "宮保雞丁", "1": "白斬雞", "menu2": "糖醋里脊", "menu3": "粉絲蒸蝦", "menu4": "魚香肉絲"}
value的類型可以是str | int | float | list | set | dict
>>> type({1:"宮保雞丁","1":"白斬雞","menu2":{1:1},"menu3":"粉絲蒸蝦",})
key必須是不可變的類型(str、tuple)
>>> {[1,2]:"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}
Traceback (most recent call last):
File "", line 1, in
{[1,2]:"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}
TypeError: unhashable type: "list"
>>> {(1,2):"宮保雞丁","menu2":"糖醋里脊","menu3":"粉絲蒸蝦","menu4":"魚香肉絲"}
{(1, 2): "宮保雞丁", "menu2": "糖醋里脊", "menu3": "粉絲蒸蝦", "menu4": "魚香肉絲"}
