python best way to read a txt code example

Example 1: python read file line by line

with open("file.txt") as file_in:
    lines = []
    for line in file_in:
        lines.append(line)

Example 2: python open and read file with

with open('pagehead.section.htm','r') as f:
    output = f.read()

Example 3: with open as file python

>>> with open('workfile') as f:
...     read_data = f.read()

>>> # We can check that the file has been automatically closed.
>>> f.closed
True