Python Pocket Reference, 3rd Edition

Specific Built-in Types

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29

Operations

All sequence operations (see Table 3, earlier in this book).

Files

The built-in open function creates a stdio file object, the most

common file interface. File objects export the method calls in

the next section. In recent releases, the type name

file can

be used as a synonym for

open when creating a file object

(but

open is the generally recommended spelling).

Also see the

open function in the section “Built-in Func-

tions,” later in this book; the

anydbm, shelve, and pickle

modules in the section “Object Persistence Modules,” later in

this book; the

os module descriptor-based file functions and

the

os.path directory path tools in the section “The os Sys-

tem Module,” later in this book; and the Python SQL data-

base API in the section “Python Portable SQL Database

API,” later in this book.

Input files

infile = open('data.txt', 'r')

Creates input file ('r' means read as text, while 'rb'

reads binary with no line-break translation). The file-

name string (e.g.,

'data.txt') maps to the current work-

ing directory, unless it includes a directory path prefix

(e.g.,

'c:\\dir\\data.txt'). The mode argument (e.g.,

'r') is optional and defaults to 'r'.

infile.read()

Reads entire file, returning its contents as a single string.

In text mode (

'r'), line-ends are translated to '\n'.In

binary mode (

'rb'), the result string can contain non-

printable characters (e.g.,

'\0').

infile.read(N)