Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | from math import sin, cos def evaluate(expression): """ Evaluates the given mathematical expression. Args: expression (str): The mathematical expression to evaluate. Returns: float: The result of the evaluation. """ # Split the expression into tokens. tokens = expression.split() # Create a stack to store the operands and operators. stack = [] # Iterate over the tokens. for token in tokens: # If the token is a number, push it onto the stack. if token.isdigit(): stack.append(float(token)) # If the token is an operator, pop the top two operands from the stack, # apply the operator to them, and push the result onto the stack. elif token in ['+', '-', '*', '/']: operand2 = stack.pop() operand1 = stack.pop() if token == '+': stack.append(operand1 + operand2) elif token == '-': stack.append(operand1 - operand2) elif token == '*': stack.append(operand1 * operand2) elif token == '/': stack.append(operand1 / operand2) # If the token is a prefix operator, pop the top operand from the stack, # apply the operator to it, and push the result onto the stack. elif token in ['sin', 'cos']: operand = stack.pop() if token == 'sin': stack.append(sin(operand)) elif token == 'cos': stack.append(cos(operand)) # If the token is an opening parenthesis, push it onto the stack. elif token == '(': stack.append('(') # If the token is a closing parenthesis, pop all operands and operators # from the stack until an opening parenthesis is encountered, then evaluate # the expression and push the result onto the stack. elif token == ')': sub_expression = [] while stack[-1] != '(': sub_expression.append(stack.pop()) stack.pop() # Remove the opening parenthesis. stack.append(evaluate(' '.join(sub_expression[::-1]))) # The final result is the top element of the stack. return stack.pop() |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | from math import sin, cos def evaluate(expression): """ Evaluates the given mathematical expression. Args: expression (str): The mathematical expression to evaluate. Returns: float: The result of the evaluation. """ # Split the expression into tokens. tokens = expression.split() # Create a stack to store the operands and operators. stack = [] # Iterate over the tokens. for token in tokens: # If the token is a number, push it onto the stack. if token.isdigit(): stack.append(float(token)) # If the token is an operator, pop the top two operands from the stack, # apply the operator to them, and push the result onto the stack. elif token in ['+', '-', '*', '/']: operand2 = stack.pop() operand1 = stack.pop() if token == '+': stack.append(operand1 + operand2) elif token == '-': stack.append(operand1 - operand2) elif token == '*': stack.append(operand1 * operand2) elif token == '/': stack.append(operand1 / operand2) # If the token is a prefix operator, pop the top operand from the stack, # apply the operator to it, and push the result onto the stack. elif token in ['sin', 'cos']: operand = stack.pop() if token == 'sin': stack.append(sin(operand)) elif token == 'cos': stack.append(cos(operand)) # If the token is an opening parenthesis, push it onto the stack. elif token == '(': stack.append('(') # If the token is a closing parenthesis, pop all operands and operators # from the stack until an opening parenthesis is encountered, then evaluate # the expression and push the result onto the stack. elif token == ')': sub_expression = [] while stack[-1] != '(': sub_expression.append(stack.pop()) stack.pop() # Remove the opening parenthesis. stack.append(evaluate(' '.join(sub_expression[::-1]))) # The final result is the top element of the stack. return stack.pop() |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 | from math import sin, cos def evaluate(expression): """ Evaluates the given mathematical expression. Args: expression (str): The mathematical expression to evaluate. Returns: float: The result of the evaluation. """ # Split the expression into tokens. tokens = expression.split() # Create a stack to store the operands and operators. stack = [] # Iterate over the tokens. for token in tokens: # If the token is a number, push it onto the stack. if token.isdigit(): stack.append(float(token)) # If the token is an operator, pop the top two operands from the stack, # apply the operator to them, and push the result onto the stack. elif token in ['+', '-', '*', '/']: operand2 = stack.pop() operand1 = stack.pop() if token == '+': stack.append(operand1 + operand2) elif token == '-': stack.append(operand1 - operand2) elif token == '*': stack.append(operand1 * operand2) elif token == '/': stack.append(operand1 / operand2) # If the token is a prefix operator, pop the top operand from the stack, # apply the operator to it, and push the result onto the stack. elif token in ['sin', 'cos']: operand = stack.pop() if token == 'sin': stack.append(sin(operand)) elif token == 'cos': stack.append(cos(operand)) # If the token is an opening parenthesis, push it onto the stack. elif token == '(': stack.append('(') # If the token is a closing parenthesis, pop all operands and operators # from the stack until an opening parenthesis is encountered, then evaluate # the expression and push the result onto the stack. elif token == ')': sub_expression = [] while stack[-1] != '(': sub_expression.append(stack.pop()) stack.pop() # Remove the opening parenthesis. stack.append(evaluate(' '.join(sub_expression[::-1]))) # The final result is the top element of the stack. return stack.pop() answer = round(evaluate('sin(35+2*4)-cos(15)'), 5) expected = -0.07209 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 67, in <module>
answer = round(evaluate('sin(35+2*4)-cos(15)'), 5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 61, in evaluate
return stack.pop()
^^^^^^^^^^^
IndexError: pop from empty list
Testing if the previous output contains the string All tests passed
: False
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | def evaluate(expression): """Evaluate an arithmetic expression represented as a string. The expression can contain the following operators: +, -, *, /, sin, cos. Parentheses are also supported. Args: expression: The expression to evaluate. Returns: The value of the expression. """ # Tokenize the expression. tokens = tokenize(expression) # Parse the tokens into an abstract syntax tree (AST). ast = parse(tokens) # Evaluate the AST. return evaluate_ast(ast) def tokenize(expression): """Tokenize an arithmetic expression. Args: expression: The expression to tokenize. Returns: A list of tokens. """ tokens = [] i = 0 while i < len(expression): c = expression[i] if c.isdigit(): # Number. number = c i += 1 while i < len(expression) and expression[i].isdigit(): number += expression[i] i += 1 tokens.append(('NUMBER', number)) elif c in '+-*/()': # Operator or parenthesis. tokens.append((c, c)) i += 1 elif c in 'sincos': # Prefix operator. prefix_op = c i += 1 while i < len(expression) and expression[i].isalpha(): prefix_op += expression[i] i += 1 tokens.append(('PREFIX_OP', prefix_op)) else: # Invalid character. raise ValueError("Invalid character: {}".format(c)) return tokens def parse(tokens): """Parse a list of tokens into an abstract syntax tree (AST). Args: tokens: A list of tokens. Returns: An AST. """ ast = [] i = 0 while i < len(tokens): token = tokens[i] if token[0] == 'NUMBER': # Number. ast.append(('NUMBER', int(token[1]))) elif token[0] in '+-*/()': # Operator or parenthesis. ast.append(token) elif token[0] == 'PREFIX_OP': # Prefix operator. ast.append(('PREFIX_OP', token[1])) i += 1 ast.append(parse(tokens)) else: # Invalid token. raise ValueError("Invalid token: {}".format(token)) i += 1 return ast def evaluate_ast(ast): """Evaluate an abstract syntax tree (AST). Args: ast: An AST. Returns: The value of the AST. """ if ast[0] == 'NUMBER': # Number. return ast[1] elif ast[0] in '+-*/': # Operator. left = evaluate_ast(ast[1]) right = evaluate_ast(ast[3]) if ast[0] == '+': return left + right elif ast[0] == '-': return left - right elif ast[0] == '*': return left * right elif ast[0] == '/': return left / right elif ast[0] == 'PREFIX_OP': # Prefix operator. operand = evaluate_ast(ast[2]) if ast[1] == 'sin': return math.sin(operand) elif ast[1] == 'cos': return math.cos(operand) else: # Invalid AST. raise ValueError("Invalid AST: {}".format(ast)) |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | def evaluate(expression): """Evaluate an arithmetic expression represented as a string. The expression can contain the following operators: +, -, *, /, sin, cos. Parentheses are also supported. Args: expression: The expression to evaluate. Returns: The value of the expression. """ # Tokenize the expression. tokens = tokenize(expression) # Parse the tokens into an abstract syntax tree (AST). ast = parse(tokens) # Evaluate the AST. return evaluate_ast(ast) def tokenize(expression): """Tokenize an arithmetic expression. Args: expression: The expression to tokenize. Returns: A list of tokens. """ tokens = [] i = 0 while i < len(expression): c = expression[i] if c.isdigit(): # Number. number = c i += 1 while i < len(expression) and expression[i].isdigit(): number += expression[i] i += 1 tokens.append(('NUMBER', number)) elif c in '+-*/()': # Operator or parenthesis. tokens.append((c, c)) i += 1 elif c in 'sincos': # Prefix operator. prefix_op = c i += 1 while i < len(expression) and expression[i].isalpha(): prefix_op += expression[i] i += 1 tokens.append(('PREFIX_OP', prefix_op)) else: # Invalid character. raise ValueError("Invalid character: {}".format(c)) return tokens def parse(tokens): """Parse a list of tokens into an abstract syntax tree (AST). Args: tokens: A list of tokens. Returns: An AST. """ ast = [] i = 0 while i < len(tokens): token = tokens[i] if token[0] == 'NUMBER': # Number. ast.append(('NUMBER', int(token[1]))) elif token[0] in '+-*/()': # Operator or parenthesis. ast.append(token) elif token[0] == 'PREFIX_OP': # Prefix operator. ast.append(('PREFIX_OP', token[1])) i += 1 ast.append(parse(tokens)) else: # Invalid token. raise ValueError("Invalid token: {}".format(token)) i += 1 return ast def evaluate_ast(ast): """Evaluate an abstract syntax tree (AST). Args: ast: An AST. Returns: The value of the AST. """ if ast[0] == 'NUMBER': # Number. return ast[1] elif ast[0] in '+-*/': # Operator. left = evaluate_ast(ast[1]) right = evaluate_ast(ast[3]) if ast[0] == '+': return left + right elif ast[0] == '-': return left - right elif ast[0] == '*': return left * right elif ast[0] == '/': return left / right elif ast[0] == 'PREFIX_OP': # Prefix operator. operand = evaluate_ast(ast[2]) if ast[1] == 'sin': return math.sin(operand) elif ast[1] == 'cos': return math.cos(operand) else: # Invalid AST. raise ValueError("Invalid AST: {}".format(ast)) |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | def evaluate(expression): """Evaluate an arithmetic expression represented as a string. The expression can contain the following operators: +, -, *, /, sin, cos. Parentheses are also supported. Args: expression: The expression to evaluate. Returns: The value of the expression. """ # Tokenize the expression. tokens = tokenize(expression) # Parse the tokens into an abstract syntax tree (AST). ast = parse(tokens) # Evaluate the AST. return evaluate_ast(ast) def tokenize(expression): """Tokenize an arithmetic expression. Args: expression: The expression to tokenize. Returns: A list of tokens. """ tokens = [] i = 0 while i < len(expression): c = expression[i] if c.isdigit(): # Number. number = c i += 1 while i < len(expression) and expression[i].isdigit(): number += expression[i] i += 1 tokens.append(('NUMBER', number)) elif c in '+-*/()': # Operator or parenthesis. tokens.append((c, c)) i += 1 elif c in 'sincos': # Prefix operator. prefix_op = c i += 1 while i < len(expression) and expression[i].isalpha(): prefix_op += expression[i] i += 1 tokens.append(('PREFIX_OP', prefix_op)) else: # Invalid character. raise ValueError("Invalid character: {}".format(c)) return tokens def parse(tokens): """Parse a list of tokens into an abstract syntax tree (AST). Args: tokens: A list of tokens. Returns: An AST. """ ast = [] i = 0 while i < len(tokens): token = tokens[i] if token[0] == 'NUMBER': # Number. ast.append(('NUMBER', int(token[1]))) elif token[0] in '+-*/()': # Operator or parenthesis. ast.append(token) elif token[0] == 'PREFIX_OP': # Prefix operator. ast.append(('PREFIX_OP', token[1])) i += 1 ast.append(parse(tokens)) else: # Invalid token. raise ValueError("Invalid token: {}".format(token)) i += 1 return ast def evaluate_ast(ast): """Evaluate an abstract syntax tree (AST). Args: ast: An AST. Returns: The value of the AST. """ if ast[0] == 'NUMBER': # Number. return ast[1] elif ast[0] in '+-*/': # Operator. left = evaluate_ast(ast[1]) right = evaluate_ast(ast[3]) if ast[0] == '+': return left + right elif ast[0] == '-': return left - right elif ast[0] == '*': return left * right elif ast[0] == '/': return left / right elif ast[0] == 'PREFIX_OP': # Prefix operator. operand = evaluate_ast(ast[2]) if ast[1] == 'sin': return math.sin(operand) elif ast[1] == 'cos': return math.cos(operand) else: # Invalid AST. raise ValueError("Invalid AST: {}".format(ast)) answer = round(evaluate('sin(35+2*4)-cos(15)'), 5) expected = -0.07209 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 137, in <module>
answer = round(evaluate('sin(35+2*4)-cos(15)'), 5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 19, in evaluate
ast = parse(tokens)
^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 89, in parse
ast.append(parse(tokens))
^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 89, in parse
ast.append(parse(tokens))
^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 89, in parse
ast.append(parse(tokens))
^^^^^^^^^^^^^
[Previous line repeated 995 more times]
RecursionError: maximum recursion depth exceeded
Testing if the previous output contains the string All tests passed
: False
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | import math def evaluate(expr): """ Evaluate a mathematical expression. The expression can be a simple number, a parenthesized expression, or a binary operation (+, -, *, /) of two expressions. Args: expr: The expression to evaluate. Returns: The value of the expression. """ # Check if the expression is a number. if expr.isdigit(): return int(expr) # Check if the expression is a parenthesized expression. if expr[0] == '(' and expr[-1] == ')': return evaluate(expr[1:-1]) # Check if the expression is a binary operation. for op in ('+', '-', '*', '/'): if op in expr: parts = expr.split(op) left = evaluate(parts[0]) right = evaluate(parts[1]) if op == '+': return left + right elif op == '-': return left - right elif op == '*': return left * right elif op == '/': return left / right # Check if the expression is a prefix operation. for op in ('sin', 'cos'): if expr.startswith(op): arg = evaluate(expr[len(op):]) if op == 'sin': return math.sin(arg) elif op == 'cos': return math.cos(arg) # The expression is invalid. raise ValueError("Invalid expression: {}".format(expr)) |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | import math def evaluate(expr): """ Evaluate a mathematical expression. The expression can be a simple number, a parenthesized expression, or a binary operation (+, -, *, /) of two expressions. Args: expr: The expression to evaluate. Returns: The value of the expression. """ # Check if the expression is a number. if expr.isdigit(): return int(expr) # Check if the expression is a parenthesized expression. if expr[0] == '(' and expr[-1] == ')': return evaluate(expr[1:-1]) # Check if the expression is a binary operation. for op in ('+', '-', '*', '/'): if op in expr: parts = expr.split(op) left = evaluate(parts[0]) right = evaluate(parts[1]) if op == '+': return left + right elif op == '-': return left - right elif op == '*': return left * right elif op == '/': return left / right # Check if the expression is a prefix operation. for op in ('sin', 'cos'): if expr.startswith(op): arg = evaluate(expr[len(op):]) if op == 'sin': return math.sin(arg) elif op == 'cos': return math.cos(arg) # The expression is invalid. raise ValueError("Invalid expression: {}".format(expr)) |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | import math def evaluate(expr): """ Evaluate a mathematical expression. The expression can be a simple number, a parenthesized expression, or a binary operation (+, -, *, /) of two expressions. Args: expr: The expression to evaluate. Returns: The value of the expression. """ # Check if the expression is a number. if expr.isdigit(): return int(expr) # Check if the expression is a parenthesized expression. if expr[0] == '(' and expr[-1] == ')': return evaluate(expr[1:-1]) # Check if the expression is a binary operation. for op in ('+', '-', '*', '/'): if op in expr: parts = expr.split(op) left = evaluate(parts[0]) right = evaluate(parts[1]) if op == '+': return left + right elif op == '-': return left - right elif op == '*': return left * right elif op == '/': return left / right # Check if the expression is a prefix operation. for op in ('sin', 'cos'): if expr.startswith(op): arg = evaluate(expr[len(op):]) if op == 'sin': return math.sin(arg) elif op == 'cos': return math.cos(arg) # The expression is invalid. raise ValueError("Invalid expression: {}".format(expr)) answer = round(evaluate('sin(35+2*4)-cos(15)'), 5) expected = -0.07209 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 57, in <module>
answer = round(evaluate('sin(35+2*4)-cos(15)'), 5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 30, in evaluate
left = evaluate(parts[0])
^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 44, in evaluate
arg = evaluate(expr[len(op):])
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 51, in evaluate
raise ValueError("Invalid expression: {}".format(expr))
ValueError: Invalid expression: (35
Testing if the previous output contains the string All tests passed
: False
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | import math def evaluate(expression): """ Evaluate an expression in the given BNF-style grammar. Args: expression (str): The expression to evaluate. Returns: float: The result of the evaluation. """ # Tokenize the expression tokens = expression.split() # Evaluate the expression result = _evaluate_expression(tokens) # Return the result return result def _evaluate_expression(tokens): """ Evaluate an expression. Args: tokens (list of str): The tokens of the expression. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # If the token is an infix operator, evaluate the left and right operands and the operator else: operator = token left_operand = _evaluate_expression(tokens[:2]) right_operand = _evaluate_expression(tokens[2:]) return _evaluate_infix_op(operator, left_operand, right_operand) def _evaluate_factor(tokens): """ Evaluate a factor. Args: tokens (list of str): The tokens of the factor. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # Otherwise, raise an error else: raise ValueError(f"Invalid token: {token}") def _evaluate_prefix_op(operator, factor): """ Evaluate a prefix operator. Args: operator (str): The operator. factor (float): The factor. Returns: float: The result of the evaluation. """ # If the operator is 'sin', return the sine of the factor if operator == 'sin': return math.sin(factor) # If the operator is 'cos', return the cosine of the factor elif operator == 'cos': return math.cos(factor) # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") def _evaluate_infix_op(operator, left_operand, right_operand): """ Evaluate an infix operator. Args: operator (str): The operator. left_operand (float): The left operand. right_operand (float): The right operand. Returns: float: The result of the evaluation. """ # If the operator is '+', return the sum of the operands if operator == '+': return left_operand + right_operand # If the operator is '-', return the difference of the operands elif operator == '-': return left_operand - right_operand # If the operator is '*', return the product of the operands elif operator == '*': return left_operand * right_operand # If the operator is '/', return the quotient of the operands elif operator == '/': return left_operand / right_operand # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | import math def evaluate(expression): """ Evaluate an expression in the given BNF-style grammar. Args: expression (str): The expression to evaluate. Returns: float: The result of the evaluation. """ # Tokenize the expression tokens = expression.split() # Evaluate the expression result = _evaluate_expression(tokens) # Return the result return result def _evaluate_expression(tokens): """ Evaluate an expression. Args: tokens (list of str): The tokens of the expression. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # If the token is an infix operator, evaluate the left and right operands and the operator else: operator = token left_operand = _evaluate_expression(tokens[:2]) right_operand = _evaluate_expression(tokens[2:]) return _evaluate_infix_op(operator, left_operand, right_operand) def _evaluate_factor(tokens): """ Evaluate a factor. Args: tokens (list of str): The tokens of the factor. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # Otherwise, raise an error else: raise ValueError(f"Invalid token: {token}") def _evaluate_prefix_op(operator, factor): """ Evaluate a prefix operator. Args: operator (str): The operator. factor (float): The factor. Returns: float: The result of the evaluation. """ # If the operator is 'sin', return the sine of the factor if operator == 'sin': return math.sin(factor) # If the operator is 'cos', return the cosine of the factor elif operator == 'cos': return math.cos(factor) # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") def _evaluate_infix_op(operator, left_operand, right_operand): """ Evaluate an infix operator. Args: operator (str): The operator. left_operand (float): The left operand. right_operand (float): The right operand. Returns: float: The result of the evaluation. """ # If the operator is '+', return the sum of the operands if operator == '+': return left_operand + right_operand # If the operator is '-', return the difference of the operands elif operator == '-': return left_operand - right_operand # If the operator is '*', return the product of the operands elif operator == '*': return left_operand * right_operand # If the operator is '/', return the quotient of the operands elif operator == '/': return left_operand / right_operand # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 | import math def evaluate(expression): """ Evaluate an expression in the given BNF-style grammar. Args: expression (str): The expression to evaluate. Returns: float: The result of the evaluation. """ # Tokenize the expression tokens = expression.split() # Evaluate the expression result = _evaluate_expression(tokens) # Return the result return result def _evaluate_expression(tokens): """ Evaluate an expression. Args: tokens (list of str): The tokens of the expression. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # If the token is an infix operator, evaluate the left and right operands and the operator else: operator = token left_operand = _evaluate_expression(tokens[:2]) right_operand = _evaluate_expression(tokens[2:]) return _evaluate_infix_op(operator, left_operand, right_operand) def _evaluate_factor(tokens): """ Evaluate a factor. Args: tokens (list of str): The tokens of the factor. Returns: float: The result of the evaluation. """ # Get the first token token = tokens[0] # If the token is a number, return the number if token.isdigit(): return float(token) # If the token is a left parenthesis, evaluate the expression inside the parentheses elif token == '(': return _evaluate_expression(tokens[1:-1]) # If the token is a prefix operator, evaluate the operator and the factor elif token in {'sin', 'cos'}: operator = token factor = _evaluate_factor(tokens[1:]) return _evaluate_prefix_op(operator, factor) # Otherwise, raise an error else: raise ValueError(f"Invalid token: {token}") def _evaluate_prefix_op(operator, factor): """ Evaluate a prefix operator. Args: operator (str): The operator. factor (float): The factor. Returns: float: The result of the evaluation. """ # If the operator is 'sin', return the sine of the factor if operator == 'sin': return math.sin(factor) # If the operator is 'cos', return the cosine of the factor elif operator == 'cos': return math.cos(factor) # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") def _evaluate_infix_op(operator, left_operand, right_operand): """ Evaluate an infix operator. Args: operator (str): The operator. left_operand (float): The left operand. right_operand (float): The right operand. Returns: float: The result of the evaluation. """ # If the operator is '+', return the sum of the operands if operator == '+': return left_operand + right_operand # If the operator is '-', return the difference of the operands elif operator == '-': return left_operand - right_operand # If the operator is '*', return the product of the operands elif operator == '*': return left_operand * right_operand # If the operator is '/', return the quotient of the operands elif operator == '/': return left_operand / right_operand # Otherwise, raise an error else: raise ValueError(f"Invalid operator: {operator}") answer = round(evaluate('sin(35+2*4)-cos(15)'), 5) expected = -0.07209 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 152, in <module>
answer = round(evaluate('sin(35+2*4)-cos(15)'), 5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 19, in evaluate
result = _evaluate_expression(tokens)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 55, in _evaluate_expression
left_operand = _evaluate_expression(tokens[:2])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 55, in _evaluate_expression
left_operand = _evaluate_expression(tokens[:2])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 55, in _evaluate_expression
left_operand = _evaluate_expression(tokens[:2])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[Previous line repeated 994 more times]
File "/usr/src/app/main.py", line 39, in _evaluate_expression
if token.isdigit():
^^^^^^^^^^^^^^^
RecursionError: maximum recursion depth exceeded while calling a Python object
Testing if the previous output contains the string All tests passed
: False
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
Given this BNF-style grammar write a Python function `evaluate(str)` that evaluates the expression <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' For example you can evaluate this sin(3 + 2 * 4) - cos(15) = -0.240302
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 | import math def evaluate(expr): """ Evaluates a mathematical expression given in a BNF-style grammar. <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' """ tokens = expr.split() return _evaluate(tokens) def _evaluate(tokens): """ Helper function for evaluate(). """ if len(tokens) == 1: return _evaluate_factor(tokens[0]) elif tokens[1] in ['+', '-']: return _evaluate_expression(tokens[0], tokens[1], tokens[2:]) elif tokens[1] in ['*', '/']: return _evaluate_term(tokens[0], tokens[1], tokens[2:]) else: raise ValueError("Invalid expression: {}".format(expr)) def _evaluate_expression(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '+': return left_value + right_value elif op == '-': return left_value - right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_term(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '*': return left_value * right_value elif op == '/': return left_value / right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_factor(token): """ Helper function for evaluate(). """ if token.isdigit(): return int(token) elif token[0] == '(' and token[-1] == ')': return _evaluate(token[1:-1]) elif token in ['sin', 'cos']: return math.sin(math.radians(_evaluate(token[3:]))) if token == 'sin' else math.cos(math.radians(_evaluate(token[3:]))) else: raise ValueError("Invalid factor: {}".format(token)) |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 | import math def evaluate(expr): """ Evaluates a mathematical expression given in a BNF-style grammar. <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' """ tokens = expr.split() return _evaluate(tokens) def _evaluate(tokens): """ Helper function for evaluate(). """ if len(tokens) == 1: return _evaluate_factor(tokens[0]) elif tokens[1] in ['+', '-']: return _evaluate_expression(tokens[0], tokens[1], tokens[2:]) elif tokens[1] in ['*', '/']: return _evaluate_term(tokens[0], tokens[1], tokens[2:]) else: raise ValueError("Invalid expression: {}".format(expr)) def _evaluate_expression(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '+': return left_value + right_value elif op == '-': return left_value - right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_term(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '*': return left_value * right_value elif op == '/': return left_value / right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_factor(token): """ Helper function for evaluate(). """ if token.isdigit(): return int(token) elif token[0] == '(' and token[-1] == ')': return _evaluate(token[1:-1]) elif token in ['sin', 'cos']: return math.sin(math.radians(_evaluate(token[3:]))) if token == 'sin' else math.cos(math.radians(_evaluate(token[3:]))) else: raise ValueError("Invalid factor: {}".format(token)) |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 | import math def evaluate(expr): """ Evaluates a mathematical expression given in a BNF-style grammar. <expression> ::= <term> | <expression> '+' <term> | <expression> '-' <term> <term> ::= <factor> | <term> '*' <factor> | <term> '/' <factor> <factor> ::= <number> | '(' <expression> ')' | <prefix-op> <factor> <prefix-op> ::= 'sin' | 'cos' <number> ::= <digit> | <number> <digit> <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' """ tokens = expr.split() return _evaluate(tokens) def _evaluate(tokens): """ Helper function for evaluate(). """ if len(tokens) == 1: return _evaluate_factor(tokens[0]) elif tokens[1] in ['+', '-']: return _evaluate_expression(tokens[0], tokens[1], tokens[2:]) elif tokens[1] in ['*', '/']: return _evaluate_term(tokens[0], tokens[1], tokens[2:]) else: raise ValueError("Invalid expression: {}".format(expr)) def _evaluate_expression(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '+': return left_value + right_value elif op == '-': return left_value - right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_term(left, op, right): """ Helper function for evaluate(). """ left_value = _evaluate(left) right_value = _evaluate(right) if op == '*': return left_value * right_value elif op == '/': return left_value / right_value else: raise ValueError("Invalid operator: {}".format(op)) def _evaluate_factor(token): """ Helper function for evaluate(). """ if token.isdigit(): return int(token) elif token[0] == '(' and token[-1] == ')': return _evaluate(token[1:-1]) elif token in ['sin', 'cos']: return math.sin(math.radians(_evaluate(token[3:]))) if token == 'sin' else math.cos(math.radians(_evaluate(token[3:]))) else: raise ValueError("Invalid factor: {}".format(token)) answer = round(evaluate('sin(35+2*4)-cos(15)'), 5) expected = -0.07209 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 79, in <module>
answer = round(evaluate('sin(35+2*4)-cos(15)'), 5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 21, in evaluate
return _evaluate(tokens)
^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 28, in _evaluate
return _evaluate_factor(tokens[0])
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/src/app/main.py", line 73, in _evaluate_factor
raise ValueError("Invalid factor: {}".format(token))
ValueError: Invalid factor: sin(35+2*4)-cos(15)
Testing if the previous output contains the string All tests passed
: False