From c599498993f873c77f1ca3ef51c1f088cf1c3269 Mon Sep 17 00:00:00 2001
From: Viraat Das <viraat.laldas@gmail.com>
Date: Thu, 4 Jun 2026 22:25:16 -0700
Subject: [PATCH] Parse the numeric day-of-week token 'd'

arrow can format a date with the single 'd' token (ISO day of week as a
number) but cannot parse it back: arrow.get("3", "d") raises because 'd'
is not handled in the parser. Add 'd' to the parseable tokens and map it to
day_of_week so a 'd'-formatted value round-trips.

Fixes #1072.
---
 arrow/parser.py      | 4 ++++
 tests/test_parser.py | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/arrow/parser.py b/arrow/parser.py
index fc3774b0..769019ce 100644
--- a/arrow/parser.py
+++ b/arrow/parser.py
@@ -550,6 +550,7 @@ def _parse_token(
             "m",
             "ss",
             "s",
+            "d",
             "x",
         ],
         value: Union[str, bytes, SupportsInt, bytearray],
@@ -645,6 +646,9 @@ def _parse_token(
             )
             parts["day_of_week"] = day_of_week - 1
 
+        elif token == "d":
+            parts["day_of_week"] = int(value) - 1
+
         elif token.upper() in ["HH", "H"]:
             parts["hour"] = int(value)
 
diff --git a/tests/test_parser.py b/tests/test_parser.py
index 7038d880..9838f89c 100644
--- a/tests/test_parser.py
+++ b/tests/test_parser.py
@@ -586,6 +586,9 @@ def test_parse_ddd_and_dddd(self):
         assert self.parser.parse("Tuesday", "dddd") == expected
         assert fr_parser.parse("mardi", "dddd") == expected
 
+        # Get first Wednesday after epoch by ISO day of week
+        assert arrow.get("3", "d") == arrow.get(1970, 1, 7)
+
         # Get first Tuesday in 2020
         expected = datetime(2020, 1, 7)
         assert self.parser.parse("Tue 2020", "ddd YYYY") == expected