将Pandas DataFrame特定值写入自定义格式文件教程

// Lines of comments
identifierX       label2 = i  label3        label4
label5
A1 = -5563.88 B2 = -4998 C3 = -203.8888 D4 = 5926.8 
E5 = 24.99876 F6 = 100.6666 G7 = 30.008 H8 = 10.9999
J9 = 1000000 K10 = 1.0002 L11 = 0.1
M12

identifierY       label2 = i  label3        label4
label5
...

import pandas as pd
import numpy as np
import string

# --- 1. 准备示例数据 (可忽略，仅用于生成模拟DataFrame) ---
# 此部分代码用于生成符合描述的随机数据，实际应用中你将直接使用已有的DataFrame
rng = np.random.default_rng(seed=42)
dfs = {
    idname: pd.DataFrame(data=[
        {
            'Labels': string.ascii_uppercase[i] + str(i + 1),
            'Numbers': rng.integers(0, 1000)
        } for i in range(20)
    ]) for idname in ['identifier1', 'identifier2', 'identifier3']
}
# -----------------------------------------------------------

# --- 2. 定义输出格式的关键参数 ---
# 确定需要从DataFrame中提取并写入文件的字段列表
desired_fields = [string.ascii_uppercase[i] + str(i + 1) for i in range(11)]
# 定义每行输出的键值对数量，例如每4个键值对换行
stride = 4
# 初始化一个空字符串，用于累积所有输出内容
outstr = ''

# --- 3. 添加文件头部注释 ---
outstr += '// comment1
// comment2
// comment3
// comment4
'

# --- 4. 遍历每个数据标识符及其对应的DataFrame ---
for idname, id_data in dfs.items():
    # 拼接每个数据块的头部信息
    outstr += f'{idname}       label2 = i \ label3        label4
label5
'

    # --- 5. 提取并格式化特定字段的值 ---
    for i, field in enumerate(desired_fields):
        # 从当前DataFrame中找到匹配的Label，并提取对应的Numbers值
        try:
            # 使用布尔索引查找特定Label对应的行，然后获取'Numbers'列的值
            value = str(id_data.loc[id_data['Labels'] == field].iloc[0]['Numbers'])
        except IndexError:
            # 处理数据缺失的情况，例如如果某个desired_field在当前DataFrame中不存在
            value = 'N/A' # 可以设置为默认值或空字符串

        # 格式化为 "Label = Value " 的形式
        outstr += f'{field} = {value} '

        # 根据stride控制换行：每当达到stride定义的数量时，添加一个换行符
        if i % stride == stride - 1:
            outstr += '
'

    # 如果最后一个数据块的键值对数量不是stride的倍数，确保其后也有换行
    if not outstr.endswith('
'):
        outstr += '
'

    # 在不同数据块之间添加一个空行，以增加可读性
    outstr += '
'

# --- 6. 打印并写入文件 ---
print("--- 生成的输出内容 ---")
print(outstr)

# 将构建好的字符串写入文件
output_filename = 'outputfile.txt'
with open(output_filename, 'w', encoding='utf-8') as fh:
    fh.write(outstr)

print(f"
数据已成功写入到文件: {output_filename}")

// comment1
// comment2
// comment3
// comment4
identifier1       label2 = i  label3        label4
label5
A1 = 89 B2 = 773 C3 = 654 D4 = 438 
E5 = 433 F6 = 858 G7 = 85 H8 = 697 
I9 = 201 J10 = 94 K11 = 526 

identifier2       label2 = i  label3        label4
label5
A1 = 500 B2 = 370 C3 = 182 D4 = 926 
E5 = 781 F6 = 643 G7 = 402 H8 = 822 
I9 = 545 J10 = 443 K11 = 450 

identifier3       label2 = i  label3        label4
label5
A1 = 165 B2 = 758 C3 = 700 D4 = 354 
E5 = 67 F6 = 970 G7 = 445 H8 = 893 
I9 = 677 J10 = 778 K11 = 759