So I have something complicated but here is a simple version of it:
i, j = 1, 2 a_1, a_2 = 1, 2 f"{a_f'{i}'} + {a_f'{j}'} = 3" == '1 + 2 = 3' I want an expression like in the left side to give a result like in the right side, the one I wrote here gives an error.
Can this be done using nested f-strings?
Without context, this seems like an XY problem. You should probably use a dict or list instead of variables, based on How do I create variable variables? For example,
dict
>>> i, j = 1, 2 >>> a = {1: 1, 2: 2} >>> f"{a[i]} + {a[j]} = 3" '1 + 2 = 3' list
>>> i, j = 0, 1 # list indexing starts at 0 >>> a = [1, 2] >>> f"{a[i]} + {a[j]} = 3" '1 + 2 = 3' Are you trying to get dynamically the variable by creating a string? If so and it is not a class attribute, the only solution on top of my head is to use globals or locals (as below), yet not recommended:
f'{globals()[f"a_{i}"]} + {globals()[f"a_{j}"]} = 3' == '1 + 2 = 3' See How to get the value of a variable given its name in a string? for more info
Nested f-strings are not supported. It is possible to create variable variables to achieve the same thing:
i, j = 1, 2 a_1, a_2 = 1, 2 v1 = globals()[f"a_{i}"] v2 = globals()[f"a_{j}"] f"{v1} + {v2} = 3" == '1 + 2 = 3' See also: How do I create variable variables?
