24 Jan Friday 17:00 Python Practice 21.01.22.
Assume the postfix expression is a string of characters separated by spaces. The operators are *, /, +, and – and the operands are assumed to be single-digit integer values. The output will be an integer result. The following are the steps how to calculate the value of the postfix expression:
- Create an empty stack called s.
- Convert the string to a list by using the string method split.
- Scan the token list from left to right.
- If the token is an operand, convert it from a string to an integer and push the value onto the s.
- If the token is an operator, *, /, +, or -, it will need two operands. Pop the s twice. The first pop is the second operand and the second pop is the first operand. Perform the arithmetic operation. Push the result back on the s.
- When the input expression has been completely processed, the result is on the stack. Pop the s and return the value.
Please create a function for calculating the value of the given postfix expressions.