Credit: Mark Lutz, author of Programming Python and Python Quick Referenc e, co-author of Learning Python
Behold the file—one of the first things that any reasonably pragmatic programmer reaches for in a programming language’s toolbox. Because processing external files is a very real, tangible task, the quality of file-processing interfaces is a good way to assess the practicality of a programming tool.
As the recipes in this chapter attest, Python shines in this task.
Files in Python are supported in a variety of layers: from the built-in
open function (a synonym for the
file object type), to
specialized tools in standard library modules such as
os, to third-party utilities available on the
Web. All told, Python’s arsenal of file tools provides several powerful
ways to access files in your scripts.
In Python, a file object is an instance of built-in type
file. The built-in function
open creates and returns a file
object. The first argument, a string, specifies the file’s path (i.e.,
the filename preceded by an optional directory path). The second
open, also a string,
specifies the mode in which to open the file. For example:
input = open('data', 'r') output = open('/tmp/spam', 'w')
open accepts a file path in which directories and files are
separated by slash characters (
regardless of the proclivities of the underlying operating system. On
systems that don’t use slashes, you can use a backslash character
\) instead, ...