From 5d8e1b6eb3bb083f372866cdef1a6242c47b4026 Mon Sep 17 00:00:00 2001
From: Robin <167366979+allrob23@users.noreply.github.com>
Date: Mon, 3 Mar 2025 22:36:34 -0300
Subject: [PATCH 1/2] perf: improve membership check performance in column
 filtering

---
 pandas/io/parsers/c_parser_wrapper.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pandas/io/parsers/c_parser_wrapper.py b/pandas/io/parsers/c_parser_wrapper.py
index 818c9f5ff6b80..8974cfea9b84b 100644
--- a/pandas/io/parsers/c_parser_wrapper.py
+++ b/pandas/io/parsers/c_parser_wrapper.py
@@ -258,8 +258,10 @@ def read(
                 )
 
                 columns = _filter_usecols(self.usecols, columns)
+                columns_set = set(columns)
 
-                col_dict = {k: v for k, v in col_dict.items() if k in columns}
+
+                col_dict = {k: v for k, v in col_dict.items() if k in columns_set}
 
                 return index, columns, col_dict
 

From 7e8c88d1b31e763a2c753c6e791cbb6524e4a38a Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 4 Mar 2025 12:52:27 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 pandas/io/parsers/c_parser_wrapper.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/io/parsers/c_parser_wrapper.py b/pandas/io/parsers/c_parser_wrapper.py
index 8974cfea9b84b..aa9f3556c8f62 100644
--- a/pandas/io/parsers/c_parser_wrapper.py
+++ b/pandas/io/parsers/c_parser_wrapper.py
@@ -260,7 +260,6 @@ def read(
                 columns = _filter_usecols(self.usecols, columns)
                 columns_set = set(columns)
 
-
                 col_dict = {k: v for k, v in col_dict.items() if k in columns_set}
 
                 return index, columns, col_dict