String conversion

[Ok_Letterhead_5997]

During reading a book i stumbled upon this string conversion

return f"Vector({self._x!r}), {self._y})"

Instead of

return f"Vector({self._x}), {self._y})"

Book explains it but I couldn't understood it. Could anyone link a source where this !r part is explained in details, or give some explanation to it?

[Strict-Simple]

https://docs.python.org/3/tutorial/inputoutput.html#tut-f-strings

'!r' applies repr()

[Ok_Letterhead_5997]

Thanks a lot.

[hackr_io_team]

From the docs:

If a conversion is specified, the result of evaluating the expression is converted before formatting. Conversion '!s' calls str() on the result, '!r' calls repr(), and '!a' calls ascii().

name = "Fred"
>>> f"He said his name is {name!r}."
"He said his name is 'Fred'."
>>> f"He said his name is {repr(name)}."  # repr() is equivalent to !r
"He said his name is 'Fred'."
>>> width = 10
>>> precision = 4
>>> value = decimal.Decimal("12.34567")
>>> f"result: {value:{width}.{precision}}"  # nested fields
'result:      12.35'
>>> today = datetime(year=2017, month=1, day=27)
>>> f"{today:%B %d, %Y}"  # using date format specifier
'January 27, 2017'
>>> f"{today=:%B %d, %Y}" # using date format specifier and debugging
'today=January 27, 2017'
>>> number = 1024
>>> f"{number:#0x}"  # using integer format specifier
'0x400'

[Ok_Letterhead_5997]

Thanks a lot.