问题 While playing with new f-strings in the recent Python 3.6 release, I've noticed the following: We create a foo variable with value bar : >>> foo = 'bar' Then, we declare a new variable, which is our f-string, and it should take foo to be formatted: >>> baz = f'Hanging on in {foo}' Ok, all going fine and then we call baz to check its value: >>> baz 'Hanging on in bar' Let's try to change the value of foo and call baz again: >>> foo = 'spam' >>> baz 'Hanging on in bar' Shouldn't it be dynamic?