Facets don't work with non-mapped geoms #48
Description
In ggplot2, it's possible to do this:
df = data.frame(a = rep(c(1,2), 100), b=rnorm(200), c=rnorm(200))
ggplot(df, aes(x=b, y=c)) + geom_point() + geom_abline(intercept=0, slope=1) + facet_wrap('a')
in plotnine, the equivalent doesn't work:
df = pd.DataFrame(dict(a=['a','b'] * 100, b=np.random.random(200), c=np.random.random(200)))
ggplot(df, aes(x='b', y='c')) + geom_point() + \
geom_abline(intercept=0, slope=1) + \
facet_wrap('a')
Out[38]: ---------------------------------------------------------------------------
NameError Traceback (most recent call last)
~/miniconda3/envs/science/lib/python3.6/site-packages/IPython/core/formatters.py in __call__(self, obj)
691 type_pprinters=self.type_printers,
692 deferred_pprinters=self.deferred_printers)
--> 693 printer.pretty(obj)
694 printer.flush()
695 return stream.getvalue()
~/miniconda3/envs/science/lib/python3.6/site-packages/IPython/lib/pretty.py in pretty(self, obj)
378 if callable(meth):
379 return meth(obj, self, cycle)
--> 380 return _default_pprint(obj, self, cycle)
381 finally:
382 self.end_group()
~/miniconda3/envs/science/lib/python3.6/site-packages/IPython/lib/pretty.py in _default_pprint(obj, p, cycle)
493 if _safe_getattr(klass, '__repr__', None) is not object.__repr__:
494 # A user-provided repr. Find newlines and replace them with p.break_()
--> 495 _repr_pprint(obj, p, cycle)
496 return
497 p.begin_group(1, '<')
~/miniconda3/envs/science/lib/python3.6/site-packages/IPython/lib/pretty.py in _repr_pprint(obj, p, cycle)
691 """A pprint that just redirects to the normal repr function."""
692 # Find newlines and replace them with p.break_()
--> 693 output = repr(obj)
694 for idx,output_line in enumerate(output.splitlines()):
695 if idx:
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/ggplot.py in __repr__(self)
82 Print/show the plot
83 """
---> 84 self.draw()
85 plt.show()
86 return '<ggplot: (%d)>' % self.__hash__()
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/ggplot.py in draw(self)
139 # assign a default theme
140 self = deepcopy(self)
--> 141 self._build()
142
143 # If no theme we use the default
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/ggplot.py in _build(self)
220 # Initialise panels, add extra data for margins & missing
221 # facetting variables, and add on a PANEL variable to data
--> 222 layout.setup(layers, self)
223
224 # Compute aesthetics to produce data with generalised
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/facets/layout.py in setup(self, layers, plot)
57 # Generate panel layout
58 data = self.facet.setup_data(data)
---> 59 self.layout = self.facet.compute_layout(data)
60 self.layout = self.coord.setup_layout(self.layout)
61 self.check_layout()
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/facets/facet_wrap.py in compute_layout(self, data)
71
72 base = combine_vars(data, self.plot.environment,
---> 73 self.vars, drop=self.drop)
74 n = len(base)
75 dims = wrap_dims(n, self.nrow, self.ncol)
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/facets/facet.py in combine_vars(data, environment, vars, drop)
520 # For each layer, compute the facet values
521 values = [eval_facet_vars(df, vars, environment)
--> 522 for df in data if df is not None]
523
524 # Form the base data frame which contains all combinations
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/facets/facet.py in <listcomp>(.0)
520 # For each layer, compute the facet values
521 values = [eval_facet_vars(df, vars, environment)
--> 522 for df in data if df is not None]
523
524 # Form the base data frame which contains all combinations
~/miniconda3/envs/science/lib/python3.6/site-packages/plotnine/facets/facet.py in eval_facet_vars(data, vars, env)
637 res = data[name]
638 else:
--> 639 res = env.eval(name, inner_namespace=data)
640 facet_vals[name] = res
641
~/miniconda3/envs/science/lib/python3.6/site-packages/patsy/eval.py in eval(self, expr, source_name, inner_namespace)
164 code = compile(expr, source_name, "eval", self.flags, False)
165 return eval(code, {}, VarLookupDict([inner_namespace]
--> 166 + self._namespaces))
167
168 @classmethod
<string> in <module>()
NameError: name 'a' is not definedIf the geom_abline call is removed, this works correctly. I think generally, if a variable isn't available to facet on, then any geoms with that variable missing should be plotted with all available data.