47 lines
1.3 KiB
Python
47 lines
1.3 KiB
Python
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#https://gist.github.com/ohaz/ed0b14a487b0569aad2d
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import ast
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def recurse(node):
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if isinstance(node, ast.BinOp):
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if isinstance(node.op, ast.Mult) or isinstance(node.op, ast.Div):
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print('(', end='')
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recurse(node.left)
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recurse(node.op)
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recurse(node.right)
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if isinstance(node.op, ast.Mult) or isinstance(node.op, ast.Div):
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print(')', end='')
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elif isinstance(node, ast.Add):
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print('+', end='')
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elif isinstance(node, ast.Sub):
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print('-', end='')
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elif isinstance(node, ast.Mult):
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print('*', end='')
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elif isinstance(node, ast.Div):
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print('/', end='')
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elif isinstance(node, ast.Num):
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print(node.n, end='')
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else:
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for child in ast.iter_child_nodes(node):
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recurse(child)
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def search_expr(node):
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returns = []
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for child in ast.iter_child_nodes(node):
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if isinstance(child, ast.Expr):
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return child
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returns.append(search_expr(child))
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for ret in returns:
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if isinstance(ret, ast.Expr):
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return ret
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return None
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formula = '4+5*7/2'
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a = ast.parse(formula)
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expr = search_expr(a)
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if expr is not None:
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recurse(expr)
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print()
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