如何在.CSV文件中过滤列，然后将这些过滤后的列保存到新的.CSV文件中？

import csv

def filter_csv(input_file, output_file, columns):
    with open(input_file, 'r') as file:
        reader = csv.reader(file)
        header = next(reader)  # 获取表头

        # 确定需要保留的列的索引
        column_indices = [header.index(column) for column in columns]

        filtered_rows = []
        for row in reader:
            filtered_row = [row[index] for index in column_indices]
            filtered_rows.append(filtered_row)

    with open(output_file, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerow(columns)  # 写入新的表头
        writer.writerows(filtered_rows)  # 写入过滤后的行数据

# 示例用法
input_file = 'input.csv'
output_file = 'output.csv'
columns_to_filter = ['Column1', 'Column3']  # 需要过滤的列

filter_csv(input_file, output_file, columns_to_filter)