title: Python: Math expression parsing
body: <p>Python:
  So I am working on a program (which is a class assignment) that will take an expression such as 3/4/5 or 32432/23423/2354325 or 3425*343/254235 or 43252+34254-2435, etc(for all operators from +,-,/,*). and will solve the expression.</p>
  
  <p>I CANT USE EVAL!!</p>
  
  <p>I cant use higher level codes, I am limited to, at most, using string manipulators from the below website to split the string.</p>
  
  <p><a href="http://docs.python.org/2/library/stdtypes.html#typesseq" rel="nofollow">http://docs.python.org/2/library/stdtypes.html#typesseq</a></p>
  
  <p>My method is to look at the expression the user enters and then use a find function to find the OPERATORS, and then use these operators and a slicing function (eg. s[0:x]). What I have is below and unfortunately it isnt working: *note that the print statements are in there for debugging purposes only.
  EDIT: why is x not defined when I run the program and enter an expression?</p>
  
  <pre><code>z= (input("expression:")).strip()
  
  def finding(z):
      if "/" in z:
          x=z.find("/")
          print("hi1")
      elif "*" in z:
          x=z.find("*")
          print("hi2")
      elif "+" in z:
          x=z.find("+")
          print("hi3")
      elif "-" in z:
          x=z.find("-")
          print("hi4")
      else:
          print("error, not math expression")
      return x
  
  def Parsing(z,x):
  
      x= finding(z)
      qw=z.s[0:x]
      print (qw)
  # take the x-value from function finding(z) and use it to split 
  
  finding(z)
  Parsing(z,x)
  </code></pre>