Python Ganso with dictionaries and examples of collections

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One, Ganso (tuple)

1. The meta-ancestor is not modifiable, usually written in parentheses in a series of items, the position of the orderly, fixed length

2. In fact, the meta-ancestor supports the general sequence operation of strings and lists, "+", "*", and the Yuanju when the Shard operation is applied will return a new Ganso

Print ((+) + (3,4)) >>>> (1,2,3,4) print ((0) >>>> (1,2,1,2,1,2,1,2) t= (1,2,3,4) print (T " ", T" 1:3 ") >>>> (1, (2,3))

3. The meta-ancestor does not provide the method of string, list and dictionary, take a stake in your relative progenitor to sort, usually first you have to convert it to a list in order to get a call using the sorting method

t= ("Z", "B".) C ") tem= list (t) Tem.sort () print (TEM) >>>> [" B "," C "," Z "]t=tuple (TEM) print (t) >>>> (" B "," C "," Z " ")

But the list inside the meta-ancestor can be modified as usual.

t= (1,[2,3],4) t[1]. [0] = "abc" Print (T) >>>>> (1,["abc", 3],4)

Two. Dictionary (dict)

1. The dictionary is unordered, that is, the result data of each query you order is not necessarily, because it is key-value type of data, do not need to pass the subscript index

2. Operation of the Dictionary:

d1={} #表示空字典D2 ={"spam": 1, "App": 2} #两项目字典D3 ={"food": {"spam": 1, "Egg": 2}} #嵌套D2 ["Apps"] #通过键进行查找D3 ["Food"] "spam" "Egg In D3 #判断egg是否存在在D3中, the Presence Returns Trued2.keys () #查询key值D2. VALUES () #查询value值D2 [key]=44# means new or modified, when the key is not present in the dictionary is added, the presence is modified Del D2[key] #删除

D2 = {"Egg", 1, "app", 2}print (d2["app"]) >>>>>>>2print (D2) >>>>>>>{"Egg", 1 , "App", 2}len (D2) >>>>>>>2# returns the length of the list of keys when merging methods: D2 = {"Egg", 1, "app", 2}d3 = {"Egg", 1, "app", 2}d2.update (D3) print (D2) >>>>>>>{"Egg", 1, "app", 2, "egg", 1, "app", 2}pop Delete method: Ability to delete a dictionary key and return its value D2 = {"Egg", 1, "app", 2}d2.pop ("egg") >>>>>>>>1print (D2) >> >>>>>>{"App", 2} Another method of creation: The condition is that all key values are the same dict.fromkeys (["A", "B"],0) >>>>>> >>>{"A": 0, "B": 0}

Three. Set (set)

A collection is an unordered, non-repeating data coincident. The main function is to

(1) go to the weight; turn a list into a collection and automatically remove duplicates

(2) Relationship test; Test the intersection of two sets of data, and set the relationship

Related actions

s1= set ([1,2,3,4,5,6,7]) s2 = set ([2,5,4,6,3,9]) print (s1.intersection (S2)) # Represents a fetch intersection >>>>>>>>{2,4,5,6,3}print (s1.union (S2)) #表示取并集 >>>>>>>>{ 1,2,3,4,5,6,7,9}print (s1.difference (S2)) #表示差集 >>>>>>>>{7,9}print (S1.isdisjiont (S2)) # Indicates whether S and S2 have intersection >>>>>>>>trues1.add (Ten) #添加1个项s1. Update ([8,9,10]) #添加多个项s1. Remove (1) #删除一项, A value of 1 (specifies which to delete, does not specify an error) S1.pop () #随机删除一个数