Python Pocket Reference, 3rd Edition

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Python Pocket Reference

adict.popitem()

Removes and returns an arbitrary (key, value) pair.

adict.pop(k [, x])

Returns adict[k] if k in adict (and removes k); else,

returns

x.

adict.fromkeys(seq [, value])

Creates a new dictionary with keys from seq and values

set to

value.

adict.iteritems(), adict.iterkeys(), adict.itervalues()

Returns an iterator over key/value pairs, keys only, or

values only.

Tuples

Tuples are immutable arrays of object references, accessed by

offset.

Literals

Tuples are written as comma-separated series of values

enclosed in parentheses. The enclosing parentheses can

sometimes be omitted (e.g., in

for loop headers and = assign-

ments).

()

An empty tuple.

(0,)

A one-item tuple (not a simple expression).

(0, 1, 2, 3)

A four-item tuple.

0, 1, 2, 3

Another four-item tuple (same as prior line); not valid in

function calls.

atuple = ('spam', (42, 'eggs'))

Nested tuples: atuple[1][1] fetches 'eggs'.