如何在python中分割固定列数的csv文件？

import csv

with open('input.csv', 'r') as file:
    # 执行后续操作

    reader = csv.reader(file)

    for row in reader:
        # 分割操作

        # 处理操作

import csv

with open('input.csv', 'r') as file:
    reader = csv.reader(file)
    for row in reader:
        # 分割操作
        columns = [row[i:i+3] for i in range(0, len(row), 3)]
        # 处理操作
        for column in columns:
            print(column)