# f.write() #String write to file
#
# f.writelines #Write a string of strings to a file. The sequence can be any iterable that yields a string, usually a list of strings
#
# f.read([size]) #Read everything in the file by default, you can specify size (bytes)
#
# f.readline([size]) #By default, one line is read at a time, and a trailing newline character is retained in the string.
#
# f.readlines([size]) #By default, the contents of the file will be saved in the list
#
# f.flush() #Write the contents of the buffer to disk
#
# f.tell() #Display the current file pointer position
#
# f.close() #Close the open file
#
# f.seek() # Perform pointer offset operation on the file, there are three modes,
#
# Generally not binary, the initial position can only be filled with 0 seek(0,0) move to the beginning of the file by default or abbreviated as seek(0)
#
# rb and rb+ can only use negative seek(x,1) to move back x (positive number) bytes from the current pointer position. If x is a negative number, the current position is moved forward by x bytes
#
# A Chinese has three bytes, and it has to move three by three. Otherwise, seek(x,2) means to move x (positive number) bytes forward and backward from the end of the file. If x is negative, it is from the end move forward x bytes
f = open("file2.txt",'w+',encoding='utf-8')
f.write("I love python\n")
f.write("python is the most beautiful language in the world!\n")
f.write("python the most beautiful language in the world?")
print(len(f.read())) #The total length of the file is 89
print(f.tell()) #After reading the file, the file pointer position is 89
f.seek(0,0) #Offset back to the file header
print(f.readline()) #Print out one line in the file (the first line)
print (f.tell()) #Display the current position of the file pointer
print(f.readline()) #Print another line (should be 2 bytes less)
print(f.tell()) #Display the current pointer position
print(f.readline()) # print the next line
print(f.tell()) #Display the current pointer position
f.seek(57,0) #Offset 9 characters forward from the tail
print(f.tell()) #Display the current pointer position
print(f.readline()) #Print out the content
f.close()
# Use r+ to open and write, be sure to pay attention to the cursor position, if there is text, it will be overwritten, because the cursor starts from the beginning