如何将嵌套列表中的多组字符串值转换为浮点数

输入列表 #

[[
     ['3.31497114423,50.803721015'],
     ['7.09205325687,50.803721015'],
     ['7.09205325687,53.5104033474'],
     ['3.31497114423,53.5104033474'], 
     ['3.31497114423,50.803721015']
         ]]

期望输出 #

[[
     [3.31497114423,50.803721015],
     [7.09205325687,50.803721015],
     [7.09205325687,53.5104033474],
     [3.31497114423,53.5104033474],
     [3.31497114423,50.803721015]
         ]]

解决方案 #

方法一：嵌套列表推导式（简洁高效）

用Python列表推导式可以一行完成转换，逻辑紧凑且执行高效：

original_list = [[
     ['3.31497114423,50.803721015'],
     ['7.09205325687,50.803721015'],
     ['7.09205325687,53.5104033474'],
     ['3.31497114423,53.5104033474'], 
     ['3.31497114423,50.803721015']
         ]]

converted_list = [[[float(coord) for coord in item[0].split(',')] for item in sublist] for sublist in original_list]

方法二：嵌套循环（直观易懂）

如果对列表推导式不熟悉，用嵌套循环分步处理更易理解：

original_list = [[
     ['3.31497114423,50.803721015'],
     ['7.09205325687,50.803721015'],
     ['7.09205325687,53.5104033474'],
     ['3.31497114423,53.5104033474'], 
     ['3.31497114423,50.803721015']
         ]]

converted_list = []
# 遍历最外层的子列表
for sublist in original_list:
    temp_sublist = []
    # 遍历子列表中的每个单元素列表
    for item in sublist:
        # 拆分逗号分隔的字符串为两个坐标字符串
        coord_strings = item[0].split(',')
        # 将每个坐标字符串转为浮点数
        coord_floats = [float(coord) for coord in coord_strings]
        temp_sublist.append(coord_floats)
    converted_list.append(temp_sublist)

两种方法最终都会得到你期望的浮点数嵌套列表。

内容的提问来源于stack exchange，提问作者Niek