Python Main focus on stack. Result should look like this: The Reverse Polish Not

Question

Python

Main focus on stack.

Result should look like this:

The Reverse Polish Notation is "19 2.14 + 4.5 2 4.3 / - &"

The result is 85.29744186046511

def evalTokens (tokens): # Evaluate RPN expression in 'tokens' stack # Put your code here (note: you will get error "pop from emply list" # if you just run the template without putting something in stack) return stack.pop 0 rp3 1" rpn- "19 2.14 + 4.5 2 4.3 / - *" # Infix: (19 + 2.14) * (4.5-2 / 4.3); answer-85.29 # Test this first; make sure your answer is 2 and not-2 rpn_tokens.split("" resultstr (evalTokens (rpn_tokens)) print( 'The Reverse Polish Noation is " ' + rpn + '''') print( 'The result is ' + result) # should be 85.29744186046511 for above test line

Explanation / Answer

def evalTokens(tokens):
stack = []
  
operators = "+-*/"
for t in tokens:
if not t in operators:
stack.append(t)
else:
a = stack.pop()
b = stack.pop()
stack.append(str(eval(b + t + a)))
return stack.pop()

rpn = "19 2.14 + 4.5 2 4.3 / - *"

rpn_tokens = rpn.split(" ")

result = str(evalTokens(rpn_tokens))
print('The Reverse Polish Notation is "' + rpn + '"')
print('The result is ' + result)

# code link: https://paste.ee/p/ck7M6

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