Oh I see. I didn't realize you were using sympify. But I don't see anywhere in the docs that indicates that sympify should understand how to deal with variable names that include a period. The function that is failing is:
http://docs.sympy.org/dev/modules/parsing.html#sympy.parsing.sympy_parser.parse_expr You can customize the parsers if you want to handle different kinds of string input. Jason moorepants.info +01 530-601-9791 On Tue, Dec 30, 2014 at 2:39 PM, Andrew Spielberg <[email protected]> wrote: > Hi Jason, > > That's true that it's an invalid character for python variables, but not > for sympy variables. For instance, doing: > > s = Symbol('base.length') > > works just fine. > > I was under the impression that sympify's inputs is treated as a string > version of a sympy expression, *NOT* a Python expression. This seems to > be what the documentation implies: > http://docs.sympy.org/dev/modules/core.html. > > Shouldn't this work? I feel like either the documentation is > misleading/ambiguous or the function is not matching the specification. > > Is there a workaround you would recommend that will properly parse periods > as Symbol does? > > -Andy S. > > On Tue, Dec 30, 2014 at 1:23 AM, Jason Moore <[email protected]> wrote: > >> Andy, >> >> The period is an invalid character for Python variables. The period is >> reserved for accessing attributes and methods of Python objects. >> >> >> Jason >> moorepants.info >> +01 530-601-9791 >> >> On Mon, Dec 29, 2014 at 5:48 PM, Andrew Spielberg <[email protected]> >> wrote: >> >>> Hi guys, >>> >>> I have a variable with a period in it (say, 'base.length'). I now wish >>> to sympify an expression, say: >>> >>> 2*base.length >>> >>> This throws an exception, >>> >>> AttributeError: 'Symbol' object has no attribute 'length' >>> >>> due to the period. Is there a way I can have the sympify read the dot >>> as just part of a variable name here? >>> >>> -Andy S. >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "sympy" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/sympy. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/sympy/CAM6e1JdM%3Dz_vcQkQo%3DLcSVO7oxznXhrVt0U2xQw5GMe8os_R1A%40mail.gmail.com >>> <https://groups.google.com/d/msgid/sympy/CAM6e1JdM%3Dz_vcQkQo%3DLcSVO7oxznXhrVt0U2xQw5GMe8os_R1A%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/CAP7f1AizO6eQJd4QwaUFWQssfsnDstKh1v%3DuKo74HF2xgqBL5A%40mail.gmail.com >> <https://groups.google.com/d/msgid/sympy/CAP7f1AizO6eQJd4QwaUFWQssfsnDstKh1v%3DuKo74HF2xgqBL5A%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAM6e1JdwJw52%3D%3DqKFWiSVfMstvwAOO-2vWuvfBfgeTjjp2%3DwSA%40mail.gmail.com > <https://groups.google.com/d/msgid/sympy/CAM6e1JdwJw52%3D%3DqKFWiSVfMstvwAOO-2vWuvfBfgeTjjp2%3DwSA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAP7f1AiEbCSsoBPUZgGTSpxKJwn0r%3DUqpqKeFBVDg6_C1PBVUQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
