22nd Python File Basics

computer = instruction + data

(CPU execution) (stored in RAM)

The computer reads the contents of the file into memory, which is actually assigned to a variable.

File Operation Flow:

• Open file: Establish the connection between the program and the file

--Reading Mode

--writing method

• Read and write files

--file_obj.read, File_obj.readline, File_obj.readlines

--file_obj.write, File_obj.writes

• Close File

File_obj.close ()

Memory----->io Buffer----> Save to disk

Open File

File_obj=open (Filename,mode)

-filename:

Original string: R ' C:\temp\text.t ' #me: The path under Linux is/, so it is not treated as a special

Escape string: ' c:\\temp/test.t '

The above two are equivalent

-mode

R (), W (), A (), B ()

R+ (), w+ (), A + () append, if the file does not exist, create

1. Read the file
   

   Var=file_obj.read ()

   -read all read back--return string

   -readline reads a line--Returns a string

   -readlines read multiple lines-Returns a list of string (list)

2. Write file:

   File_obj.write (Content_obj)

   -write f.write (content_obj + ' \ n ')
   

   -writelines

3. Close File

   File_obj.close ()

4. Remove the ' \ n ' from the read-back string

   Str=str.rstrip (' \ n ') rstrip--> removes the right-most

   Because ReadLine---> string + ' \ n ', print comes with a return key ' \ n ', so if you don't do it, you'll make a blank line.
   

5. Reading and writing of numeric data

   When writing, use STR to convert to string + ' \ n '

   When reading back, use int, float to convert to numeric data.

   ' \ n ' is a non-printable character in ASCII

Eg1:file_obj=open ('/home/wuxy/test.txt ', ' R ')

S=fiel_obj.read ()---A string

Print S

File_obj.close ()

22nd Python File Basics