python data structures book

This article mainly introduces the list of Python data structures, the tuples array, the dictionary dict, the list, and the detailed introduction of the tuples and strings as sequences. The following describes the specific content of the Python data structure, I hope you wil

the list List.pop ([index=-1]]) removes an element from the list (the last element by default) and returns the value of the element list.remove (obj) Removes the first occurrence of a value in a list list.reverse () Reverse list elements List.sort (Cmp=none, Key=none, Reverse=false) sort the original list list.clear () empty list list.copy () copy list

Array Design of arrays The design of an array is initially dependent on memory allocations, so the space must be pre-requested before use. This allows the array to have the following characteristics: 1, the request space after the size fixed, can no longer change (data overflow problem); 2, there is space continuity in memory performance, in the middle there will be no other programs need to call the data

Quick sorting of data structures and algorithms implemented by Python This article describes how to quickly sort data structures and algorithms implemented by Python. Share it with you for your reference. The specific analysis is

1. ListPython has 6 built-in types of sequences, but the most common are lists and tuples.The operations that a sequence can perform include indexing, slicing, adding, multiplying, and checking members.In addition, Python has built-in methods for determining the length of the sequence and determining the maximum and bottom elements.A list is the most common type of Python

Python data structures and algorithms-algorithm analysisAn interesting problem often occurs, that is, two seemingly different programs. Which one is better? To answer this question, we must know that the program differs greatly from the algorithm representing the program. the algorithm is a general command that solves the problem. provides a solution to any insta

List of Python data structures and tuples Sequence: A sequence is a data structure that contains elements that are numbered (starting at 0). A typical sequence consists of a list, a string, and a tuple. Where the list is mutable (can be modified), and tuples and strings are immutable (once created are fixed). The s

Python cookbook (data structures and algorithms) keeps the dictionary orderly. This example describes how to keep the dictionary in order by using Python. We will share this with you for your reference. The details are as follows: Problem:When creating a dictionary and performing iteration or serialization operations o

Let's review the basic concepts of stacks and queues: The same point: from the "Data structure" point of view, they are all linear structures, that is, the relationship between the data elements is the same. The difference: A stack is a linear table that restricts insertions and deletions only at one end of the table. A queue is a linear table that qualifies onl

Bucket sortBarrel sequencing has been used since the 1956, and the basic idea of the algorithm is proposed by E.J.ISSAC and R.c.singleton.This algorithm is like having 11 barrels, numbered from 0~10. Each occurrence of a number, in the corresponding number of buckets put aA little flag, and then just count the few small flags in each bucket OK. For example, there are 1 small flags in bucket 2nd, indicating2 appeared once, and in the 3rd barrels there were 1 small flags, indicating that 3 appeare

the old zoo. Back to the topic, notice that tuples within tuples do not lose their identities.You can access the items in a tuple by using a pair of parentheses to indicate the location of an item, just as we use the list. This is called the index operator. We use new_zoo[2] to access the third item in the New_zoo. We use new_zoo[2][2] to access the third item of the third project of the New_zoo tuple. Contains a tuple of 0 or 1 item objectives. An empty tuple consists of a pair of empty parent

Several data structures in the python collection module (Counter, OrderedDict, namedtup) The collection module has several data structures that we may use. Counter is a sub-class of the dictionary and is responsible for counting a dictionary. It supports + addition, subtract

'] = ' B ' dic[' c '] = ' c ' odic = ordereddict () odic[' a '] = ' a ' odic[' b '] = ' B ' odic[' c '] = ' C ' Print (' Unordered dictionary: ', dic) print (' Ordered dictionary: ', odic) print (' \ n ')Namedtup type, a dictionary-like tuple that can be converted to a dictionaryPrint (' Namedtup type application ') Deng = namedtuple (' Deng ', [' X ', ' y ']) i = Deng (x = 11,y = y) print (' I's value: ', i) print (' Add two values: ', i[0]+i [1]) Print (' Add by attribute: ', i.x+i.y) m,n = i

Variables store the data in memory. This means that there is a space in memory when creating variables. Based on the data type of the variable, the interpreter allocates the specified memory and determines what data can be stored in memory.Variables in Python do not need to be declared , and the assignment of variables

of the list without specifying indexSpecifies index, which pops an element from the index, and the index bounds throws a indexerror errorComplexity of Time:Do not specify an index of O (1)Specifies that the index is O (n) because subsequent elements may occur in memory after the insertion (the list is stored sequentially in memory)Clear (), NoneClears all elements of the list, leaving an empty listList Other actionsReverse ()-NoneReverses the list element, returning noneModify an existing objec

add subscribers to the class attribute X_lsit list, all Publishers share all subscribers.For example, Xiao Ming, small army subscribed to Cang teacher, small red small yellow to subscribe to the wave teacher, but Cang teacher update the film, due to share the subscribers, led to small red and small yellow also received new film notice, this is obviously a mistake.So Cang teacher and wave teacher X_list must be independent, need to write in __init__ inside, written self.x_list, so Cang teacher a

I. Data typeThere are six standard data types in Python: Number (numeric) String (String) List (lists) Tuple (tuple) Sets (collection) Dictionary (dictionary) In addition to the list and dictionary dictionaries, the data types are immutable data