如何将文件输出格式化成特定数量的数据列？

def format_data_columns(file_path, num_columns):
    # 读取文件
    with open(file_path, 'r') as file:
        data = file.readlines()

    # 解析数据
    parsed_data = [line.strip().split(',') for line in data]

    # 格式化数据列
    formatted_data = []
    for row in parsed_data:
        formatted_row = []
        for i in range(num_columns):
            if i < len(row):
                formatted_row.append(row[i])
            else:
                formatted_row.append('')
        formatted_data.append(formatted_row)

    # 输出格式化数据
    for row in formatted_data:
        print(','.join(row))

# 示例调用
format_data_columns('input.txt', 3)