Python study notes - (3) file operations

The set operation and its corresponding operator means 
that there is no insertion in the set, only addition, because after all, it is unordered

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Vergil Zhang

list_1 = [1, 4, 5, 7, 3, 6, 7, 9]
list_1 = set(list_1)
print(list_1, type(list_1))

list_2 = set([2, 6, 0, 66, 22, 8])
print(list_1,list_2)

#Intersection print ( list_1.intersection 
(list_2))
 print (list_1 & list_2 ) #Union
 print ( list_1.union(list_2))
 print (list_1 | list_2) #Difference
 , list_1 has and list_2 does not have print (list_1.difference (list_2))
 print (list_1 - list_2)



list_3 = set([1,3,7 ])
 print (list_3.issubset(list_1)) #Judging           whether it is a subset 
print (list_1.issuperset(list_3)) #Judging         whether it is a parent set

#Reverse difference set, take out two mutually exclusive 
print (list_1.symmetric_difference(list_2))
 print (list_1 ^ list_2)

list_4 = set([5,6,8 ])
 print (list_3.isdisjoint(list_4)) #return             true if the two sets do not intersect

#Add 
list_1.add( ' x ' ) to the collection
list_1.update(['a', 'v', 'b'])
print(list_1)

#Delete list_1.remove 
( ' a ' )           #Deleting non-existent elements will report an error list_1.discard 
( ' v ' )      #Deleting non-existing elements will not report an error

print (len(list_1))       # length of list_1 
print ( ' a '  in list_1)         # judge whether 'a' is in list_1

#Judging whether each element in x is in list_1 
x = {1, 3 }
 print (x.issubset(list_1))
 print (x <= list_1)
 #Judging whether each element in x is in list_1 
print (list_1.issuperset(x))
 print (list_1 >= x)

·File operation 
File operation steps: 
1. Open the file, get the file handle and assign it to a variable 
2. Operate the file through the handle 
3. Close the file 

File operation mode: 
w: write only 
r: read only 
a: append 
r+: read Write, read first, then write at the end of the file 
w+: write read, create a file first, write, then read (useless) 
a+: append read and write rb: binary file read, network transmissions are automatically closed 
with binary files with open() as file object name:

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Vergil Zhang


#data = open("yesterday.txt", encoding='utf-8').read()
#print(data)

#Get the file handle 
file = open( " PLANET.txt " , ' r ' , encoding= ' utf-8 ' )
 # print(file.write("I love Beijing Tiananmen")) #Just append content, doing other operations It will report an error 
# print(file.read())

#Read file 
for line in file.readlines():
     print (line.strip())
 # low loop method 
for index,line in enumerate(file.readlines()):
     if index == 9 :
         print ( ' --- --------This line does not print lyrics ----------------- ' )
         continue 
    print (line.strip())

#推荐
count = 0
for line in file:
    if count == 9:
        print(line)
        count += 1
        continue
    print(line)
    count += 1

print (file.tell()) #Print       out the position of the handle, based on the number of characters 
print (file.readline())
 print (file.tell())

file.seek(0) #return         to the first character

print (file.encoding) #The         encoding of the file

print (file.fileno()) #File             number , operating system maintenance, no need to pay attention

print (file.isatty()) #Whether             it is a terminal device

print (file.seekable()) #Whether the           cursor can be moved

print (file.flush()) #The      contents of the cache are flushed to the hard disk

#Force flash to hard disk

#Simulation progress bar 
import sys
 import time
 for i in range(20 ):
    sys.stdout.write("#")
    sys.stdout.flush()
    time.sleep(0.1)

file.close()
'''
file = open("PLANET.txt", 'a', encoding='utf-8')
file.truncate(10)
file.close()

file = open("PLANET.txt", 'w+', encoding='utf-8')
file.write("lalallalallala........")
file.close()

file = open("PLANET.txt", 'rb')
print(file.readline())
file.close()
'''
file_old = open("PLANET.txt", 'r', encoding="utf-8")
file_new = open( " PLANET_after.txt " , ' w ' , encoding= " utf-8 " )
 for line in file_old:
     if  " I am your planet around you "  in line:
        line = line.replace( " I am your planet " , " Vergil is Ann's planet " )
    file_new.write(line)
file_old.close()
file_new.close()

#使用自动关闭
with open("PLANET.txt", 'r', encoding="utf-8") as file:
    for line in file:
        print(line.strip())