Evaluation of variable as f-string

[Thomas Passin]

On 1/27/2023 5:10 PM, Christian Gollwitzer wrote:
> Am 27.01.23 um 21:43 schrieb Johannes Bauer:
>> I don't understand why you fully ignore literally the FIRST example I 
>> gave in my original post and angrily claim that you solution works 
>> when it does not:
>>
>> x = { "y": "z" }
>> s = "-> {x['y']}"
>> print(s.format(x = x))
>> Traceback (most recent call last):
>>    File "<stdin>", line 1, in <module>
>> KeyError: "'y'"
>>
>> This. Does. Not. Work.
> 
> It's because "you're holding it wrong!". Notice the error message; it 
> says that the key 'y' does not exist.
> 
> 
> (base) Apfelkiste:Abschlussmeeting chris$ ipython
> Python 3.8.8 (default, Apr 13 2021, 12:59:45)
> Type 'copyright', 'credits' or 'license' for more information
> IPython 7.22.0 -- An enhanced Interactive Python. Type '?' for help.
> 
> In [1]: x = { "y": "z" }
> 
> In [2]: s = "-> {x[y]}"
> 
> In [3]: print(s.format(x = x))
> -> z
> 
> In [4]:
> 
>      Christian

Oops, that's not quite what he wrote.

You: s = "-> {x[y]}"    # Works
Him: s = "-> {x['y']}"  # Fails