Python函数分组逻辑异常：匹配子列表元素生成字典不符合预期

需求说明 #

编写group_by_category函数，检查colors子列表的元素是否存在于food的子列表文本中，基于categ_cols中的颜色首字母生成字典。

现有代码 #

def group_by_category(categs_names, categs_subs, text_subs):
    temp_dict = {name: [] for name in categs_names}

    for categ_index, category_list in enumerate(categs_subs):
        for substring in category_list:
            for sublist in text_subs:
                for text in sublist:
                    if substring in text:
                        temp_dict[categs_names[categ_index]].append(text)
                    else:
                        temp_dict[categs_names[categ_index]].append('None')
    return temp_dict

categs_cols = ['y', 'r', 'g']
food = [['banana is yellow', 'apple is red', 'pear is green' ] , ['lettuce is green' ,'pasta is yellowish','sugar is brown'] ]
colors = [[ 'yellow', 'yellowish'  ], ['red'], ['green']]
grouped_cols = group_by_category(categs_cols, colors, food)
print(grouped_cols)

预期与实际结果 #

预期结果 #

{'y': ['banana is yellow', 'pasta is yellowish'], 'r': ['None', 'apple is red'], 
 'g': ['pear is green', 'lettuce is green']}

实际运行结果 #

{'y': ['banana is yellow', 'None', 'None', 'None', 'pasta is yellowish', 'None', 'None', 'None', 'None', 'None', 'pasta is yellowish', 'None'], 'r': ['None', 'apple is red', 'None', 'None', 'None', 'None'], 'g': ['None', 'None', 'pear is green', 'lettuce is green', 'None', 'None']}

问题分析 #

原代码的核心问题是循环逻辑混乱：

• 多层嵌套循环导致同一文本被重复处理：每遍历一个颜色子串，就会对所有文本执行一次“匹配则添加文本，不匹配则添加'None'”的操作，产生大量冗余的None和重复的匹配项。
• 没有实现“每个文本仅针对对应类别判断一次”的逻辑，而是无差别重复遍历。

修正后的代码 #

def group_by_category(categs_names, categs_subs, text_subs):
    # 建立类别与对应颜色子串的映射
    categ_sub_map = dict(zip(categs_names, categs_subs))
    result = {name: [] for name in categs_names}
    
    # 遍历每个food子列表，为每个类别生成对应结果
    for sublist in text_subs:
        for categ, substrings in categ_sub_map.items():
            matched_text = None
            # 在当前子列表中查找第一个匹配的文本
            for text in sublist:
                if any(sub in text for sub in substrings):
                    matched_text = text
                    break
            # 加入结果，无匹配则填'None'
            result[categ].append(matched_text if matched_text else 'None')
    
    return result

categs_cols = ['y', 'r', 'g']
food = [['banana is yellow', 'apple is red', 'pear is green' ] , ['lettuce is green' ,'pasta is yellowish','sugar is brown'] ]
colors = [[ 'yellow', 'yellowish'  ], ['red'], ['green']]
grouped_cols = group_by_category(categs_cols, colors, food)
print(grouped_cols)

运行结果 #

{'y': ['banana is yellow', 'pasta is yellowish'], 'r': ['apple is red', 'None'], 'g': ['pear is green', 'lettuce is green']}

注：此结果与用户预期的r项存在差异，推测是用户预期结果的笔误。如果需要r项为['None', 'apple is red']，可调整子列表的遍历顺序或匹配规则。

内容的提问来源于stack exchange，提问作者Gogo