Python中对bounding box浮点数保留6位小数失败求助

处理Bounding Box列表 #

直接用嵌套列表推导式遍历每个数值，执行四舍五入保留6位小数：

bbox_list = [[7.426758, 47.398349, 7.850835593464796, 47.68617800490421], 
             [7.850835593464796, 47.398349, 8.274913186929592, 47.68617800490421], 
             [8.274913186929592, 47.398349, 8.698990780394388, 47.68617800490421]]

# 保留6位小数
rounded_bbox_list = [[round(num, 6) for num in bbox] for bbox in bbox_list]
print(rounded_bbox_list)

输出结果：

[[7.426758, 47.398349, 7.850836, 47.686178], 
 [7.850836, 47.398349, 8.274913, 47.686178], 
 [8.274913, 47.398349, 8.698991, 47.686178]]

处理Bounding Box字典 #

先把字符串值分割为单个浮点数，四舍五入后可选择保留数值列表或重新拼接成字符串：

方式1：保留数值列表作为字典值 #

bbox_dict = {49: '7.850835593464796,49.12532302942521,8.274913186929592,49.413152034329414', 
             17: '7.850835593464796,47.9740070098084,8.274913186929592,48.26183601471261', 
             71: '10.395301154253572,49.70098103923361,10.819378747718368,49.988810044137814'}

rounded_bbox_dict = {}
for key, val in bbox_dict.items():
    nums = [round(float(num_str), 6) for num_str in val.split(',')]
    rounded_bbox_dict[key] = nums

print(rounded_bbox_dict)

输出结果：

{49: [7.850836, 49.125323, 8.274913, 49.413152], 
 17: [7.850836, 47.974007, 8.274913, 48.261836], 
 71: [10.395301, 49.700981, 10.819379, 49.98881]}

方式2：重新拼接为字符串（保持原格式） #

rounded_bbox_dict_str = {}
for key, val in bbox_dict.items():
    nums = [str(round(float(num_str), 6)) for num_str in val.split(',')]
    rounded_bbox_dict_str[key] = ','.join(nums)

print(rounded_bbox_dict_str)

输出结果：

{49: '7.850836,49.125323,8.274913,49.413152', 
 17: '7.850836,47.974007,8.274913,48.261836', 
 71: '10.395301,49.700981,10.819379,49.98881'}

Pandas正确处理方式 #

如果坚持用Pandas，可将数据转成DataFrame后调用round()方法，再转回原格式：

处理列表 #

import pandas as pd

df = pd.DataFrame(bbox_list)
rounded_df = df.round(6)
rounded_bbox_list_pd = rounded_df.values.tolist()

处理字典 #

# 字典转DataFrame并转换数值类型
df_dict = pd.DataFrame([val.split(',') for val in bbox_dict.values()], index=bbox_dict.keys()).astype(float)
rounded_df_dict = df_dict.round(6)

# 转回数值列表格式的字典
rounded_bbox_dict_pd = rounded_df_dict.to_dict('index')
# 转回字符串格式的字典
rounded_bbox_dict_str_pd = {k: ','.join(map(str, v)) for k, v in rounded_df_dict.to_dict('index').items()}

内容的提问来源于stack exchange，提问作者Daniel AG