如何在Python中将含numpy数组的列表保存为指定格式CSV

你当前的问题出在直接将sigma1转成字符串写入文件——numpy数组的默认字符串输出自带换行，列表的字符串表示还会包含多余的括号和换行符，导致最终输出格式不符合预期。以下是两种可行的解决方案：

方案一：用csv模块规范写入（推荐） #

利用csv.writer的writerow方法，自动处理逗号分隔逻辑：

import numpy as np
import csv

sigma1 = [np.array([[0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109]])]

# 取出数组并扁平化转为一维Python列表
data = sigma1[0].flatten().tolist()

with open('Data_sigma.csv', 'w', newline='') as f:
    writer = csv.writer(f)
    writer.writerow(['sigma'])  # 写入标题行
    writer.writerow(data)       # 自动用逗号分隔数据为单行

方案二：手动拼接字符串写入（适合简单场景） #

直接将数组元素转成字符串后拼接成逗号分隔的单行：

import numpy as np

sigma1 = [np.array([[0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109],
       [0.02109]])]

data = sigma1[0].flatten().tolist()
data_str = ','.join(map(str, data))  # 拼接成逗号分隔的字符串

with open('Data_sigma.csv', 'w') as f:
    f.write('sigma\n')
    f.write(data_str)

两种方案最终都会生成符合预期的输出：

sigma
0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109,0.02109

内容的提问来源于stack exchange，提问作者user19862793