Python Files

Read a file

myFile = open("/myPath/myFile.txt","r") print(myFile.read()) myFile.close()
  • It is important to close the file if you open it with open()
  • The "r" indicates "read" permission, other permissions will be demonstrated later.
  • If no file path is specified before the file name, it will look for the file in the directory of your coding file.

Safe file reading (takes care of closing after)

with open ("/myPath/myFile.txt","r") as myFile: print(myFile.read())
  • This is a better way to read a file, so that you don't accidentally leave files open.
  • This takes care of closing the file even if your program ends due to an exception.

Read one line at a time

with open ("/myPath/myFile.txt","r") as myFile: for myLine in myFile: print(myLine)
  • This is useful if you want to work with each line as you read it.

Write a file

with open ("/myPath/myFile.txt","w") as myFile: myFile.write("This text")
  • The "w" indicates "write".
  • If this file exists, it will overwrite what is currently on it. If not, it will create the file.

Append text to a file

with open ("/myPath/myFile.txt","a") as myFile: myFile.write("Text to add")
  • This will add text after the text that is already in the file.
  • The only code difference from writing the file is the "a" instead of "w".

Challenge

Write code that will write a file that stores a list of names, append a name to that file, then read the file and display its contents.

Completed