Container summary

  Containers ：python Several official containers
    list： list
    set： aggregate
    tuple： Tuples
    dict： Dictionaries

One , list ：
ls = []
ls = list()
Access elements through subscripts

Common ways to list ：
append( Elements )# Append an element to the end of the list
insert( Index position , Elements )# In a specific place , Additive elements
clear() # Clear the list
count(element)# Count the number of occurrences of elements
index(element)# The index of the query element appears for the first time , If it doesn't exist , Throw an exception
 remove(element)    # Remove the corresponding element through the element
 pop([index])# Delete the last element by default , If a location is specified , Then delete the element at the corresponding position  
 reverse()    # Flip list order
 copy()    # Shallow copy objects （ Replication of heap objects ）
 extend( Iteratable object )    # Merge list
 sort()# Sort

Multidimensional list ：
[[],[],[],[],[]]

Two ,Set（ aggregate ）：
1、 Definition set aggregate
s = { Elements 1, Elements 2...}
s = set()
s = set({ Elements 1, Elements 2...})
s = set([ Elements 1, Elements 2...])    # take list Convert to set object
ls = list({ Elements 1, Elements 2...})    # take set Convert to list object

 2, Common methods
add( Elements )        # add to
clear
copy
 remove    # Remove... By the element itself , If the element does not exist , Throw an exception
 discard    # Remove... By the element itself , If the element does not exist , Then do nothing
 pop()    # Remove elements at random
intersection# intersection
 union    # Combine
difference# Difference set
update    # Merge sets

3、 ... and , Tuples （tuple）：
     Tuples are immutable data types .
     Elements in tuples are not allowed to be modified or changed .

Definition of tuple ：
t = ()# Define tuples , But it's not recommended to use , Because tuples are immutable
t = (" In the spring ", " In the summer ", " autumn ", " In the winter ")    # It is recommended to initialize the value when defining
（2）, Common methods ：
count# Number of statistical elements
 index# Query the index of the element
Four , Dictionaries （dict）：
dictionary, It's a use key-value The structure of key value pairs stores data
python in key Can't repeat , Otherwise, the data will be overwritten
key The type of can only be string ,value Any type
How to access dictionary values ：
Use... In the dictionary key obtain key Corresponding value
d["name"]# obtain name Corresponding value , If it's time to key non-existent , Throw an exception
d.get("age")# You can also use get Method , If key non-existent , Then return to None
Common ways of Dictionary
 clear
 copy
fromkeys()# Convert other iteratable objects to dictionaries
 get
items()        # Iterate out each key value pair [(),()]
keys()        #
value()
setdefault()    # newly added key and value
 update
 popitem        # Pairs are returned in LIFO (last-in, first-out) order
pop(key)        # adopt key, Delete key Corresponding key value pair