There's got to be an easy way to do this

[Tim Peters]

[Lindstrom Greg]
> I am reading in a phone number field and would like to throw away
> everything except the digits.

Simplest:

>>> def isdigit(c):
...     return c in "0123456789"
...
>>> filter(isdigit, "(555) 333.2221")
'5553332221'
>>>

Fastest:  Read the docs for string.translate(); set it to do identity (i.e.,
no) translation, and pass everthing *except* digits in its optional third
("delete these") argument.