# how to append to a symbolic expression in a loop?

This must be super basic, but i don't get how to do the classic

```
for i in list:
expression = expression + i
```

symbolically. I want to add new terms to the expression, and the "==" notation does not mash well with that.

An .append() method would make sense, but i was not able to find one.

the

`= SR.zero()`

is the solution. I had defined expression as a symbolic variable and then it didn't work.can you please move this to a proper answer so i can upvote it?