Evaluates mathematical strings, formatted in infix notation, passed in as a command line argument.
No outside dependencies.
$ python calculate.py "1 + 2 * 3 + 4"
11.0
Turn debug on, with the -d flag. With debug on, the application will also print the tokens for both the entered infix notation, as well as the postfix notion, before printing the answer.
$ python calculate.py -d "1 + 2 * 3"
Number => 1.0
Operator => +
Number => 2.0
Operator => *
Number => 3.0
1.0 + 2.0 * 3.0
Number => 1.0
Number => 2.0
Number => 3.0
Operator => *
Operator => +
1.0 2.0 3.0 * +
7.0
Here is a list of allowed binary operators:
- ADD: "+"
- SUBTRACT: "-"
- MULTIPLY: "*"
- DIVIDE: "/"
- POWER: "^"
- MOD: "%"
- L_PARENTHESIS: "("
- R_PARENTHESIS: ")"
All other characters will be ignored by the lexer as it parses the equation. Because of this, you'll get syntax errors if you try:
$ python calculate.py "1 + 2 * 3 + A"
SyntaxError: Operator: [+], at string position: 10
1 + 2 * 3 [+] A
NOTE: Unary operators, including the negation operator, are not supported.