FileIO.md

File input and output

We use file objects to manipulate files

f = open('workfile', 'w')

The second argument is the mode

mode	function
r	read only, default if mode is omitted
w	write, create a file to write; existing file will be erased
a	append, open for writing, but written data is added to the end
r+	read and write, keeping the file
w+	read and write, erasing the file

Use the with statement for clean handling and closing of file objects

with open('workfile') as f:
    # do things with the file object

When reading from a file, there is a cursor that advances. This ensures you will only ever read the file once.

f.read() # reads and returns the entire file, but remember that the cursor will now be at the end

f.readline() # reads and returns until encountering a newline '\n' character

f.write('My new line\n') # writes the text to the open file

f.seek(0) # returns the cursor to the beginning of the file