用于修改csv文件、复制和格式化列以及保存输出的Python

import csv

def modify_csv_file(file_path, column_index, new_value):
    with open(file_path, 'r') as file:
        reader = csv.reader(file)
        rows = list(reader)  # 将CSV文件内容读取为列表

    for row in rows:
        row[column_index] = new_value  # 修改指定列的值

    with open(file_path, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerows(rows)  # 将修改后的内容写回到CSV文件

# 示例：将第三列的值修改为"新值"
modify_csv_file('example.csv', 2, '新值')

import csv

def copy_and_format_column(file_path, source_column_index, target_column_index, format_string):
    with open(file_path, 'r') as file:
        reader = csv.reader(file)
        rows = list(reader)  # 将CSV文件内容读取为列表

    for row in rows:
        source_value = row[source_column_index]
        formatted_value = format_string.format(source_value)  # 格式化源列的值
        row.insert(target_column_index, formatted_value)  # 将格式化后的值插入目标列

    with open(file_path, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerows(rows)  # 将修改后的内容写回到CSV文件

# 示例：将第一列的值复制到第四列，并格式化为两位小数
copy_and_format_column('example.csv', 0, 3, '{:.2f}')

import csv

def save_output(file_path, output_file_path):
    with open(file_path, 'r') as file:
        reader = csv.reader(file)
        rows = list(reader)  # 将CSV文件内容读取为列表

    # 进行修改、复制和格式化列的操作...

    with open(output_file_path, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerows(rows)  # 将修改后的内容写入新的CSV文件

# 示例：将修改后的CSV文件保存为output.csv
save_output('example.csv', 'output.csv')