Files in Python

• While databases such as MySQL and Postgres are popular and widely used in many web applications, there is still a large amount to data that is stored and exchanged sing text file formats.

• Popular formats are

  • Comma Seperated Values,
  • Java Script Object Notation (JSON)
  • YAML
  • Plain text
  • Binary

• Reading a Text file using python

  • Refer Here for the sample to read the whole contents of the file

• Read Partial content from a text file

  • Refer Here

• With Statement for opening the files: In python we can use with block to open the files, The advantage of using this approach is as soon as the block is executed, file will be closed automatically.

  • Refer Here for the changeset containing with statements

• Writing files:

  • In python we use open function to open the file and while opening the file we can specify the mode.
  • Python has following file opening modes
    • r: This is default mode and it opens file for reading
    • w: The Write mode. This opens a file for writing, creates a new file if the file doesnot exist and overrites the contents if the file already exists
    • x: This creates a new file. This operation fails if the file exists
    • a: This opens file in append mode and creates the new file if a file does not exist
    • b: This opens a file in binary mode
  • Lets try to write a program which asks the user to enter the name, course etc and stores the data in a text file. Refer Here
  • Enhance this code by doing the following

  1. Add new enquiry information
  2. Print all the data
  3. quit
  Enter your choice? (1 or 2) 
  

  • Refer Here for basic skeleton.