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TXT Text file storage

​ Save the data as TXT The operation of text is very simple , and TXT Text is compatible with almost any platform , But there is also a disadvantage , Is not conducive to retrieval . So if the requirements for retrieval and data structure are not high , The pursuit of convenience first , You can use TXT This storage .

​ Let's take a look at using Python preservation TXT Method of text file .

1. Instance Introduction

​ We use the movie example website https://ssr1.scrape.center/ For example , Crawl to the home page 10 Data of the film , Then store the relevant information as TXT Text format .

​ The example code is as follows ：

import requests
from pyquery import PyQuery as pq
import re

url = 'https://ssr1.scrape.center/'
html = requests.get(url).text
doc = pq(html)
items = doc('.el-card').items()
file = open('movies.txt', 'w', encoding='utf-8')
for item in items:
    #  The movie name 
    name = item.find('a > h2').text()
    file.write(f' name :{
      name}\n')
    #  Category 
    categories = [item.text()
                  for item in item.find('.categories button span').items()]
    file.write(f' Category :{
      categories}\n')
    #  Release time 
    published_at = item.find('.info:contains( release )').text()
    published_at = re.search('(\d{4}-\d{2}-\d{2})', published_at). group(
        1) if published_at and re.search('\d{4}-\d{2} -\d{2}', published_at) else None
    file.write(f' Release time ：{
      published_at}\n')
    #  score 
    score = item.find('p.score').text()
    file.write(f' score :{
      score}\n')
    file.write(f'{
      "="*50}\n')
file.close()  #  here close Want to be with for At the same level , If in for Internal error reporting 

​ The purpose here is mainly to demonstrate the storage method of files , So it's not necessary requests Exception handling part . First , use requests To extract the homepage of the website HTML Code , And then use it pyquery The parsing library converts the name of the movie 、 Category 、 Release time 、 Extract the scoring information .

​ utilize Python Provided open Method to open a text file , Get a file operation object , Here it is assigned as file, Each part of the information extracted , using file Object's write Method to write this information to the file .

​ After all extraction , call close Methods will file Object closed , In this way, the content of the website home page is successfully written into the text .

​ Run the program , It can be found that a movies.txt file , Its contents are shown in the figure .

​ It can be seen that , The content of the movie information has been saved in text form .

​ Let's look back at what we need to know in this section , That is, text writing , In fact, that is open、write、close The usage of these three methods .

​ open The first parameter of the method is the name of the target file to be saved ; The second parameter represents how the data is written to the text , Here is w, Indicates that... Is written in an overwritten manner ; The third parameter specifies the file code as utf-8. Last , After writing , You also need to call close Method to close the file object .

2. Open mode

​ In the example just now ,open The second parameter of the method is set to w, In this way, the source file will be emptied every time text is written , Then write the new content to the file .w It's just a way to open files , The following is a brief introduction to several other .

• r： Open a file as read-only , It means that you can only read the contents of the file , It cannot be written . This is also the default mode .

• rb： Open a file in binary read-only mode , Usually used to open binary files , For example, audio 、 picture 、 Video etc. .

• r+： Open a file read-write , You can read and write files .

• rb+： Open a file in binary read-write mode , You can also read and write , Just read and write binary data .

• w： Open a file by writing . If the file already exists , Then cover it . If the file does not exist , Create a new file .

• wb： Open a file by binary writing . If the file already exists , Then cover it . If the file does not exist , Create a new file .

• w+： Open a file read-write . If the file already exists , Then cover it . If the file does not exist , Create a new file .

• wb+： Open a file in binary read-write format . If the file already exists , Then cover it . If the file does not exist , Create a new file .

• a： Open a file in append mode . If the file already exists , Then the file pointer will be placed at the end of the file . in other words , New content will be written after existing content . If the file does not exist , Create a new file to write .

• ab： Open a file by binary append . If the file already exists , Then the file pointer will be placed at the end of the file . in other words , New content will be written after existing content . If the file does not exist , Create a new file to write .

• That is to say , New content will be written after existing content . If the file does not exist , Create a new file to write .

• a+： Open a file read-write . If the file already exists , Then the file pointer will be placed at the end of the file . Append mode when the file opens . If the file does not exist , Create a new file for reading and writing .

• ab+： Open a file by binary append . If the file already exists , Then the file pointer will be placed at the end of the file , If the file does not exist , Create a new file for reading and writing .

3. Simplify writing

​ There is another shorthand for file writing , Is the use of with as grammar . When with At the end of the control block , The file will close automatically , It means that there is no need to call close Method .
This storage method can be abbreviated as follows ：

with open('movies.txt', 'w', encoding-'utf-8') as file:
    file.write(f' name :{
      name}\n')
    file.write(f' Category : {
      categories}\n')
    file.write(f' Release time : {
      published_at}\n')
    file.write(f' score :{
      score}\n')

​ The above is the use of Python Save results as TXT Method of file , This method is simple and easy to use 、 Efficient operation , Is one of the most basic data storage methods .