Python Pocket Reference, 3rd Edition

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Python Pocket Reference

The for Statement

for target in sequence:

suite

[else:

suite]

The for loop is a sequence iteration that assigns items in

sequence to target and runs the first suite for each. The for

statement runs the else suite if the loop exits without hitting

a

break statement. target can be anything that can appear on

the left side of an

= assignment statement (e.g., for (x, y) in

tuplelist:

).

In Version 2.2, this works by first trying to obtain an iterator

object with

iter(sequence) and then calling that object’s

next() method repeatedly until StopIteration is raised (see

the section “The yield Statement,” later in this book). In ear-

lier versions, or if no iterator object can be obtained (e.g., no

__iter__ method is defined), this works instead by repeat-

edly indexing

sequence at successively higher offsets until an

IndexError is raised.

The pass Statement

pass

This is a do-nothing placeholder statement, and is used when

syntactically necessary.

The break Statement

break

This immediately exits the closest enclosing while or for

loop statement, skipping its associated else (if any).