8.3. Text files and lines

A text file can be thought of as a sequence of lines, much like a Python string can be thought of as a sequence of characters. For example, this is a sample of a text file which records mail activity from various individuals in an open source project development team:

From stephen.marquard@uct.ac.za Sat Jan  5 09:14:16 2008
Return-Path: <postmaster@collab.sakaiproject.org>
Date: Sat, 5 Jan 2008 09:12:18 -0500
To: source@collab.sakaiproject.org
From: stephen.marquard@uct.ac.za
Subject: [sakai] svn commit: r39772 - content/branches/
Details: http://source.sakaiproject.org/viewsvn/?view=rev&rev=39772
...

The entire file of mail interactions is available from

www.py4e.com/code3/mbox.txt

and a shortened version of the file is available from

www.py4e.com/code3/mbox-short.txt

These files are in a standard format for a file containing multiple mail messages. The lines which start with “From “ separate the messages and the lines which start with “From:” are part of the messages. For more information about the mbox format, see https://en.wikipedia.org/wiki/Mbox.

To break the file into lines, there is a special character that represents the “end of the line” called the newline character.

In Python, we represent the newline character as a backslash-n in string constants. Even though this looks like two characters, it is actually a single character. When we look at the variable by entering “stuff” in the interpreter, it shows us the \n in the string, but when we use print to show the string, we see the string broken into two lines by the newline character.

stuff = 'Hello World!' print(stuff) stuff = 'Hello\nWorld!' print(stuff) stuff = 'X\nY' print(stuff) len(stuff)

You can also see that the length of the string X\nY is three characters because the newline character is a single character.

So when we look at the lines in a file, we need to remember that there is a special invisible character called the newline at the end of each line that marks the end of the line.

So the newline character separates the characters in the file into lines.

Q-2: A(n) character separates characters of a file into lines.

Q-3: How many characters is \n (the newline character) counted as?

• 0
• A newline does count as some number of characters.
• 1
• Despite being two characters when written, a newline character is only counted as one character.
• 2
• Despite being two characters when written, a newline character is only counted as one character.
• As many as it takes to finish the line.
• There is a definite character count for a newline character that is not dependent on the other characters in a line.

You have attempted of activities on this page