From 2effff093420d9cf240c6c5e3f32333022d9a9e5 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sun, 8 Mar 2026 13:31:53 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20[pypinyin/style/=5Futils.py]=20opti?=
 =?UTF-8?q?mize=20has=5Ffinals=20with=20module-level=20constant?=
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Move the list of symbols in has_finals to a module-level tuple _NO_FINALS_SYMBOLS.
This avoids creating the list on every function call and allows for slightly
more efficient iteration.

Measured improvement:
Baseline: 0.2752µs per call
After: 0.2795µs per call
The difference is within measurement error, but the change follows best practices
by avoiding repeated allocations and using a constant for iteration.

Co-authored-by: mozillazg <485054+mozillazg@users.noreply.github.com>
---
 pypinyin/style/_utils.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pypinyin/style/_utils.py b/pypinyin/style/_utils.py
index 7156f279..01a26915 100644
--- a/pypinyin/style/_utils.py
+++ b/pypinyin/style/_utils.py
@@ -84,10 +84,13 @@ def replace_symbol_to_no_symbol(pinyin):
     return RE_NUMBER.sub('', value)
 
 
+# 鼻音: 'm̄', 'ḿ', 'm̀', 'ń', 'ň', 'ǹ' 没有韵母
+_NO_FINALS_SYMBOLS = ('m̄', 'ḿ', 'm̀', 'ń', 'ň', 'ǹ')
+
+
 def has_finals(pinyin):
     """判断是否有韵母"""
-    # 鼻音: 'm̄', 'ḿ', 'm̀', 'ń', 'ň', 'ǹ ' 没有韵母
-    for symbol in ['m̄', 'ḿ', 'm̀', 'ń', 'ň', 'ǹ']:
+    for symbol in _NO_FINALS_SYMBOLS:
         if symbol in pinyin:
             return False