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88b6caa30a
* Create infix_to_prefix_conversion.py * Create postfix_evaluation.py * Update balanced_parentheses.py
51 lines
1.8 KiB
Python
51 lines
1.8 KiB
Python
"""
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Output:
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Enter a Postfix Equation (space separated) = 5 6 9 * +
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Symbol | Action | Stack
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-----------------------------------
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5 | push(5) | 5
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6 | push(6) | 5,6
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9 | push(9) | 5,6,9
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| pop(9) | 5,6
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| pop(6) | 5
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* | push(6*9) | 5,54
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| pop(54) | 5
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| pop(5) |
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+ | push(5+54) | 59
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Result = 59
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"""
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import operator as op
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def Solve(Postfix):
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Stack = []
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Div = lambda x, y: int(x/y) # integer division operation
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Opr = {'^':op.pow, '*':op.mul, '/':Div, '+':op.add, '-':op.sub} # operators & their respective operation
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# print table header
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print('Symbol'.center(8), 'Action'.center(12), 'Stack', sep = " | ")
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print('-'*(30+len(Postfix)))
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for x in Postfix:
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if( x.isdigit() ): # if x in digit
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Stack.append(x) # append x to stack
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print(x.rjust(8), ('push('+x+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
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else:
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B = Stack.pop() # pop stack
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print("".rjust(8), ('pop('+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
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A = Stack.pop() # pop stack
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print("".rjust(8), ('pop('+A+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
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Stack.append( str(Opr[x](int(A), int(B))) ) # evaluate the 2 values poped from stack & push result to stack
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print(x.rjust(8), ('push('+A+x+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
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return int(Stack[0])
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if __name__ == "__main__":
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Postfix = input("\n\nEnter a Postfix Equation (space separated) = ").split(' ')
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print("\n\tResult = ", Solve(Postfix))
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