Technical questionAccepted answer
What does = (equal) do in f-strings inside the expression curly brackets?
ibarrond
Jan 9
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The usage of {} in Python f-strings is well known to execute pieces of code and give the result in string format. However, what does the '=' at the end of the expression mean?
log_file = open("log_aug_19.txt", "w")
console_error = '...stuff...' # the real code generates it with regex
log_file.write(f'{console_error=}')
python1 answer
Accepted answer · original discussion
juanpa.arrivillaga
PermalinkJan 9
This is actually a brand-new feature as of Python 3.8.
Added an
=specifier to f-strings. An f-string such asf'{expr=}'will expand to the text of the expression, an equal sign, then the representation of the evaluated expression.
Essentially, it facilitates the frequent use-case of print-debugging, so, whereas we would normally have to write:
f"some_var={some_var}"
we can now write:
f"{some_var=}"
So, as a demonstration, using a shiny-new Python 3.8.0 REPL:
>>> print(f"{foo=}")
foo=42
>>>
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user459872Permalink
Jan 9
I would recommend to check out this f-string debugging in Python 3.8 blog.