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POint() argument must be a string or a number
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  1. POint() argument must be a string or a number
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    copied!<p>I got an error. I did quick googling and it did not help me well.</p> <p>I added the whole code, well kind of whole code. request from a user.</p> <pre><code>from derp_node import * ############################################################################## # parse ############################################################################## def parse(tokens, i = 0): """parse: tuple(String) * int -&gt; (Node, int) From an infix stream of tokens, and the current index into the token stream, construct and return the tree, as a collection of Nodes, that represent the expression. NOTE: YOU ARE NOT ALLOWED TO MUTATE 'tokens' (e.g. pop())!!! YOU MUST USE 'i' TO GET THE CURRENT TOKEN OUT OF 'tokens' """ if tokens == []: raise TypeError("Error: Empty List.") elif tokens[int(i)] == '*': tokens.remove(int(i)) return mkMultiplyNode(parse(tokens), parse(tokens)) elif tokens[int(i)] == '//': tokens.remove(int(i)) return mkDivideNode(parse(tokens), parse(tokens)) elif tokens[int(i)] == '+': tokens.remove(int(i)) return mkAddNode(parse(tokens), parse(tokens)) elif tokens[int(i)] == '-': tokens.remove(int(i)) return mkSubtractNode(parse(tokens), parse(tokens)) elif tokens[int(i)].isdigit(): return mkLiteralNode(tokens.remove(int(i))) elif not tokens[int(i)].isdigit(): return mkVariableNode(tokens.remove(int(i))) else: raise TypeError("Error: Invalid Input") ############################################################################## # main ############################################################################## def main(): """main: None -&gt; None The main program prompts for the symbol table file, and a prefix expression. It produces the infix expression, and the integer result of evaluating the expression""" print("Hello Herp, welcome to Derp v1.0 :)") inFile = input("Herp, enter symbol table file: ") symTbl = {} for line in open(inFile): i = line.split() symTbl[i[0]] = int(i[1]) print("Derping the symbol table (variable name =&gt; integer value)...") for variable in sorted(symTbl): print(variable + " =&gt; " + str(symTbl[variable])) # STUDENT: CONSTRUCT AND DISPLAY THE SYMBOL TABLE HERE print("Herp, enter prefix expressions, e.g.: + 10 20 (RETURN to quit)...") # input loop prompts for prefix expressions and produces infix version # along with its evaluation while True: prefixExp = input("derp&gt; ") if prefixExp == "": break # STUDENT: GENERATE A LIST OF TOKENS FROM THE PREFIX EXPRESSION prefixLst = prefixExp.split() # STUDENT: CALL parse WITH THE LIST OF TOKENS AND SAVE THE ROOT OF # THE PARSE TREE. tokens = [] parseLst = parse(prefixLst, tokens) # STUDENT: GENERATE THE INFIX EXPRESSION BY CALLING infix AND SAVING # THE STRING infixLst = infix(parseLst) print("Derping the infix expression:") # STUDENT: EVALUTE THE PARSE TREE BY CALLING evaluate AND SAVING THE # INTEGER RESULT print("Derping the evaluation:") print("Goodbye Herp :(") if __name__ == "__main__": main() </code></pre> <p>The error I received is: </p> <pre><code> File "derpNew.py", line 31, in parse if tokens[int(i)] == '*': TypeError: int() argument must be a string or a number, not 'list' </code></pre> <p>If I remove the int() from the variable <code>i</code>, then I would get this error: <code>TypeError: list indices must be integers, not list</code></p> <p>Am I suppose to convert the list to tuple? Any help would be great. Thank you.</p> <p>If you guys are curious how I am calling the parse. I put this under main function.</p> <pre><code> tokens = [] parseLst = parse(tokens, i) </code></pre> <p><strong>EDIT:</strong> The loop:</p> <pre><code>while True: prefixExp = input("derp&gt; ") if prefixExp == "": break prefixLst = prefixExp.split() tokens = [] parseLst = parse(tokens, i) </code></pre>
 

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