Python File IO

https://www.youtube.com/watch?v=cIaOisyd7lE IO is input and output. STDIN and STOUT are special files on the computer.

Opening File

Open/Close

You must manually open/close the file

file = open("file.txt", 'r')
contents = file.read()
file.close()

With Open

This automatically closes the file afterwards

with open("file.txt", 'r') as file:
	# operations

Reading File

singleline = file.readline() # returns just one line as a string
lineslist = file.readlines() # returns alist of all lines
contents = file.read() # returns the entire file as a string
# parse through each line
for line in file:
	print(line)

readline()

readline(size=-1, /)

Read entire file with readline()

    currentline = data_file.readline()
    while currentline:
        print(currentline.rstrip())
        currentline = data_file.readline()
    data_file.close()

readlines()

readlines(size=-1, /)

read()

read(size=-1, /)

tell()

Prints the file position pointer. By default it is at position 0. Everytime you:

• readline, pointer increases by current line’s character count

seek()

Change the value of the file position pointer.