Allowed characters in Python function names

Question

Are there any other allowed characters in Python function names except alphabetical characters, numbers, and underscores? If yes, what are they?

Ovine

google it: pasteur.fr/formation/infobio/python/ch02s03.html – Yogini

possible duplicate of Valid characters in a python class name – Dave

possible duplicate of What is the naming convention in Python for variable and function names? – Picot

@danny Conventional != allowed. – Yodle

@delnan you are right. – Picot

Answer 1

In Python 3 many characters are allowed:

identifier   ::=  xid_start xid_continue*
id_start     ::=  <all characters in general categories Lu, Ll, Lt, Lm, Lo, Nl, 
                   the underscore, and characters with the Other_ID_Start property>
id_continue  ::=  <all characters in id_start, plus characters in the categories 
                   Mn, Mc, Nd, Pc and others with the Other_ID_Continue property>
xid_start    ::=  <all characters in id_start whose NFKC normalization 
                   is in "id_start xid_continue*">
xid_continue ::=  <all characters in id_continue whose NFKC normalization 
                   is in "id_continue*">

The Unicode category codes mentioned above stand for:

Lu - uppercase letters
Ll - lowercase letters
Lt - titlecase letters
Lm - modifier letters
Lo - other letters
Nl - letter numbers
Mn - nonspacing marks
Mc - spacing combining marks
Nd - decimal numbers
Pc - connector punctuations
Other_ID_Start - explicit list of characters in PropList.txt 
                 to support backwards compatibility
Other_ID_Continue - likewise

The complete list of every character can be found on Unicode.org.

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In Python 2.x it was limited to just letters, numbers, and underscore. From the docs:

identifier ::=  (letter|"_") (letter | digit | "_")*
letter     ::=  lowercase | uppercase
lowercase  ::=  "a"..."z"
uppercase  ::=  "A"..."Z"
digit      ::=  "0"..."9"

Ampere

Point to any version of the Python 3.x docs, and the answer is yes :) eg: docs.python.org/3.2/reference/lexical_analysis.html#identifiers – Felixfeliza

@JonClements D'oh! Edited. – Ampere