How to add a bar on a sympy symbol?

Question

I want to define sympy symbols such that when I display them I get a bar on them. I tried the following one:

c1bar, c2bar, c3bar, ubar, alphabar = sympy.symbols(r'$\bar{c_1} \bar{c_2} \bar{c_3} \bar{u} \bar{\alpha}$')

I then try to display it: display(alphabar) but I get: $\displaystyle \bar{\alpha}$$

How to fix this?

Answer 1

Just remove the $ sign: SymPy automatically detect if you provided Latex syntax. So your example becomes:

c1bar, c2bar, c3bar, ubar, alphabar = sympy.symbols(r'\bar{c_1} \bar{c_2} \bar{c_3} \bar{u} \bar{\alpha}')

Note that the bar is trying to cover both the symbol and the subscript, but it falls short. As far as I know, \bar only cover a single character. You can write:

c1bar, c2bar, c3bar, ubar, alphabar = sympy.symbols(r'\bar{c}_1 \bar{c}_2 \bar{c}_3 \bar{u} \bar{\alpha}')

Or you can replace \bar with \overline :

c1bar, c2bar, c3bar, ubar, alphabar = sympy.symbols(r'\overline{c_1} \overline{c_2} \overline{c_3} \overline{u} \overline{\alpha}')