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    <p>This looks like a parsing problem, and thus I am compelled to present a solution based on parsing techniques.</p> <p>While it may seem that you want to 'split' this string, I think what you actually want to do is 'tokenize' it. Tokenization or lexxing is the compilation step before parsing. I have amended my original example in an edit to implement a proper recursive decent parser here. This is the easiest way to implement a parser by hand.</p> <pre><code>import re patterns = [ ('number', re.compile('\d+')), ('*', re.compile(r'\*')), ('/', re.compile(r'\/')), ('+', re.compile(r'\+')), ('-', re.compile(r'\-')), ] whitespace = re.compile('\W+') def tokenize(string): while string: # strip off whitespace m = whitespace.match(string) if m: string = string[m.end():] for tokentype, pattern in patterns: m = pattern.match(string) if m: yield tokentype, m.group(0) string = string[m.end():] def parseNumber(tokens): tokentype, literal = tokens.pop(0) assert tokentype == 'number' return int(literal) def parseMultiplication(tokens): product = parseNumber(tokens) while tokens and tokens[0][0] in ('*', '/'): tokentype, literal = tokens.pop(0) if tokentype == '*': product *= parseNumber(tokens) elif tokentype == '/': product /= parseNumber(tokens) else: raise ValueError("Parse Error, unexpected %s %s" % (tokentype, literal)) return product def parseAddition(tokens): total = parseMultiplication(tokens) while tokens and tokens[0][0] in ('+', '-'): tokentype, literal = tokens.pop(0) if tokentype == '+': total += parseMultiplication(tokens) elif tokentype == '-': total -= parseMultiplication(tokens) else: raise ValueError("Parse Error, unexpected %s %s" % (tokentype, literal)) return total def parse(tokens): tokenlist = list(tokens) returnvalue = parseAddition(tokenlist) if tokenlist: print 'Unconsumed data', tokenlist return returnvalue def main(): string = '2+24*48/32' for tokentype, literal in tokenize(string): print tokentype, literal print parse(tokenize(string)) if __name__ == '__main__': main() </code></pre> <p>Implementation of handling of brackets is left as an exercise for the reader. This example will correctly do multiplication before addition.</p>
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    1. POHow do I split a string into a list?
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    1. COI'm reading up on tokenizing now to understand it. So I'm not able too say where the problem is though I think it's in the fact that this script will eval * and / at the same time, which is incorrect. 8/2*2 this string should print a result of 2, but it prints a result of 8.
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    2. COexcuse me im wrong, always took bomdas literally turns out multiplication and division are equal in order of predecnce and whichever is occurs first is evaluated first
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    3. COIn `tokenize`: Why use `re` to remove whitespace over a built-in string function?
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