The sympify() function is used to convert any arbitrary expression such that it can be used as a SymPy expression. Normal Python objects such as integer objects are converted in SymPy. Integer, etc.., strings are also converted to SymPy expressions.
>>> expr="x**2+3*x+2" >>> expr1=sympify(expr) >>> expr1 >>> expr1.subs(x,2)
The above code snippet gives the following output −
12
Any Python object can be converted in SymPy object. However, since the conversion internally uses eval() function, unsanitized expression should not be used, else SympifyError is raised.
>>> sympify("x***2")
---------------------------------------------------------------------------
SympifyError: Sympify of expression ‘could not parse ‘x***2” failed, because of exception being raised.
The sympify() function takes following arguments: * strict: default is False. If set to True, only the types for which an explicit conversion has been defined are converted. Otherwise, SympifyError is raised. * evaluate: If set to False, arithmetic and operators will be converted into their SymPy equivalents without evaluating expression.
>>> sympify("10/5+4/2")
The above code snippet gives the following output −
4
>>> sympify("10/5+4/2", evaluate=False)
The above code snippet gives the following output −
10/5+4/2