how to replace zeros in an array with variables in python? For example, I have array A $[0,0,0,2,4,6,0,0,0,0],$ and I want to replace $0$ values with X$1,$X$2,$X$3,$X$7,$X$8,$X$9,$X$10($keeping indices$).$ I will need to solve the system of equations in the future

Expected result: A$\_$updated$[$X$1,$X$2,$X$3,2,4,6,$X$7,$X$8,$X$9,$X$10]$