Python Pocket Reference, 3rd Edition

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Python Pocket Reference

• Class names commonly begin with an uppercase letter

(e.g.,

MyClass).

• The first (leftmost) argument in a class method function

is commonly named

self.

Specific Statements

The following sections describe all Python statements. Each

section lists the statement’s syntax formats, followed by

usage details. For compound statements, each appearance of

a suite in a statement format stands for one or more other

statements, possibly indented as a block under a header line.

A suite must be indented under a header if it contains

another compound statement (

if, while, etc.); otherwise, it

can appear on the same line as the statement header. The fol-

lowing are both valid constructs:

if x < 42:

print x

while x: x = x -1

if x < 42: print x

Assignment

target = expression

target1 = target2 = expression

target1, target2 = expression1, expression2

target1, target2,... = same-length-sequence

(target1, target2,...) = same-length-sequence

[target1, target2,...] = same-length-sequence

Assignments store references to objects in targets. Expres-

sions yield objects. Targets can be simple names (

X), quali-

fied attributes (

X.attr), or indexes and slices (X[i], X[i:j]).

The second format assigns an

expression object to each tar-

get. The third format pairs targets with expressions, left to

right. The last three formats assign components of any

sequence to corresponding targets, from left to right. The

sequence ...