Twig how to use variable variable(same as in php $$var)?

Question

symfony

Hello,
there is an output of a link to an image depending on the format:
{{post.images . {format} . url}}
how to set format as a variable?

Answer 1

twig.sensiolabs.org/doc/functions/attribute.html

Answer 2

The approach itself is not very correct. I think that it is better to write a getter with the necessary logic in the model, although here you need to look in more detail.