Use LaTeX symbols in sympy expressions

Question

I would like to do some calculations and then have those plotted using sympy. I want to use consistent notation, so I need to define a symbol which will be printed as $\Delta_l^y$.

What I have tried so far:

delta__i_0 = sympy.symbols('Delta__i_0')
sympy.pprint(delta__i_0)

which works fine. Unfortunately

delta__y_l = sympy.symbols('Delta__y_l')
sympy.pprint(delta__y_l)

does not really look nice. Any ideas?

Answer 1

From the command line Python interpreter, you could use sympy.printing.latex. For example,

import sympy as sym
import sympy.printing as printing
delta__y_l = sym.symbols('Delta__y_l')
print(printing.latex(delta__y_l))

prints

\Delta^{y}_{l}

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Or, using IPython notebook, call sym.init_printing() to enable pretty-printing: