mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 13:31:07 +00:00
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
"""
|
|
Output:
|
|
|
|
Enter a Postfix Equation (space separated) = 5 6 9 * +
|
|
Symbol | Action | Stack
|
|
-----------------------------------
|
|
5 | push(5) | 5
|
|
6 | push(6) | 5,6
|
|
9 | push(9) | 5,6,9
|
|
| pop(9) | 5,6
|
|
| pop(6) | 5
|
|
* | push(6*9) | 5,54
|
|
| pop(54) | 5
|
|
| pop(5) |
|
|
+ | push(5+54) | 59
|
|
|
|
Result = 59
|
|
"""
|
|
|
|
import operator as op
|
|
|
|
def Solve(Postfix):
|
|
Stack = []
|
|
Div = lambda x, y: int(x/y) # integer division operation
|
|
Opr = {'^':op.pow, '*':op.mul, '/':Div, '+':op.add, '-':op.sub} # operators & their respective operation
|
|
|
|
# print table header
|
|
print('Symbol'.center(8), 'Action'.center(12), 'Stack', sep = " | ")
|
|
print('-'*(30+len(Postfix)))
|
|
|
|
for x in Postfix:
|
|
if( x.isdigit() ): # if x in digit
|
|
Stack.append(x) # append x to stack
|
|
print(x.rjust(8), ('push('+x+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
|
|
else:
|
|
B = Stack.pop() # pop stack
|
|
print("".rjust(8), ('pop('+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
|
|
|
|
A = Stack.pop() # pop stack
|
|
print("".rjust(8), ('pop('+A+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
|
|
|
|
Stack.append( str(Opr[x](int(A), int(B))) ) # evaluate the 2 values poped from stack & push result to stack
|
|
print(x.rjust(8), ('push('+A+x+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format
|
|
|
|
return int(Stack[0])
|
|
|
|
|
|
if __name__ == "__main__":
|
|
Postfix = input("\n\nEnter a Postfix Equation (space separated) = ").split(' ')
|
|
print("\n\tResult = ", Solve(Postfix))
|