diff --git a/Lib/fractions.py b/Lib/fractions.py index cb05ae7c2003f0..937b5110bb0da1 100644 --- a/Lib/fractions.py +++ b/Lib/fractions.py @@ -170,7 +170,11 @@ def _round_to_figures(n, d, figures): (?P0(?=[0-9]))? (?P[0-9]+)? (?P[,_])? - (?:\.(?P[0-9]+))? + (?:\. + (?=[,_0-9]) # lookahead for digit or separator + (?P[0-9]+)? + (?P[,_])? + )? (?P[eEfFgG%]) """, re.DOTALL | re.VERBOSE).fullmatch @@ -499,6 +503,7 @@ def _format_float_style(self, match): minimumwidth = int(match["minimumwidth"] or "0") thousands_sep = match["thousands_sep"] precision = int(match["precision"] or "6") + frac_sep = match["frac_separators"] or "" presentation_type = match["presentation_type"] trim_zeros = presentation_type in "gG" and not alternate_form trim_point = not alternate_form @@ -552,6 +557,9 @@ def _format_float_style(self, match): if trim_zeros: frac_part = frac_part.rstrip("0") separator = "" if trim_point and not frac_part else "." + if frac_sep: + frac_part = frac_sep.join(frac_part[pos:pos + 3] + for pos in range(0, len(frac_part), 3)) trailing = separator + frac_part + suffix # Do zero padding if required. diff --git a/Lib/test/test_fractions.py b/Lib/test/test_fractions.py index d1d2739856c092..ad7fcbfc90a538 100644 --- a/Lib/test/test_fractions.py +++ b/Lib/test/test_fractions.py @@ -1322,6 +1322,8 @@ def test_format_e_presentation_type(self): # Thousands separators (F('1234567.123456'), ',.5e', '1.23457e+06'), (F('123.123456'), '012_.2e', '0_001.23e+02'), + # Thousands separators for fractional part (or for integral too) + (F('1234567.123456'), '.5_e', '1.234_57e+06'), # z flag is legal, but never makes a difference to the output (F(-1, 7**100), 'z.6e', '-3.091690e-85'), ] @@ -1447,6 +1449,12 @@ def test_format_f_presentation_type(self): (F('1234567'), ',.2f', '1,234,567.00'), (F('12345678'), ',.2f', '12,345,678.00'), (F('12345678'), ',f', '12,345,678.000000'), + # Thousands separators for fractional part (or for integral too) + (F('123456.789123123'), '._f', '123456.789_123'), + (F('123456.789123123'), '.7_f', '123456.789_123_1'), + (F('123456.789123123'), '.9_f', '123456.789_123_123'), + (F('123456.789123123'), '.,f', '123456.789,123'), + (F('123456.789123123'), '_.,f', '123_456.789,123'), # Underscore as thousands separator (F(2, 3), '_.2f', '0.67'), (F(2, 3), '_.7f', '0.6666667'), @@ -1623,6 +1631,11 @@ def test_invalid_formats(self): '.f', '.g', '.%', + # Thousands separators before precision + '._6e', + '._6f', + '._6g', + '._6%', # Z instead of z for negative zero suppression 'Z.2f' # z flag not supported for general formatting diff --git a/Misc/NEWS.d/next/Library/2025-04-07-10-20-16.gh-issue-87790.X2SjJe.rst b/Misc/NEWS.d/next/Library/2025-04-07-10-20-16.gh-issue-87790.X2SjJe.rst new file mode 100644 index 00000000000000..be2a30d69cab45 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-04-07-10-20-16.gh-issue-87790.X2SjJe.rst @@ -0,0 +1,2 @@ +Support underscore and comma as thousands separators in the fractional part +for :class:`~fractions.Fraction`'s formatting. Patch by Sergey B Kirpichev.