use format with tex fraction expression in matplotlib python
Solution 1:
You need to escape the curled brackets ({) with another curled bracket.
r'$\frac{{{}}}{{8}}$'.format(i)
Here the inner most bracket pair in {{{}}} is used for formatting. The escape pair {{ is replaced by a single bracket during formatting. Hence r'$\frac{{{}}}{{8}}$'.format(1) will result in r'$\frac{1}{8}$', which is then a valid MathText string.