Python匹配字典键替换列表元素时输出原列表问题求解

• 核心错误是替换前调用了i.upper()将原字符串转为全大写，但字典中存储的键是大小写敏感的德语月份（首字母大写、其余小写），全大写后的字符串不存在与字典键匹配的子串，因此替换完全不生效，还会错误修改原字符串的大小写。
• 循环逻辑冗余：外层遍历字典键、内层遍历列表的写法，会多次遍历整个列表，效率较低。

data = ['18. September 2021', '7. Juni 1946', 'Mai 2021, 19', '16.9.2021']

dictionary = {"Januar":"January","Februar":"February","März":"March","April":"April","Mai":"May","Juni":"June",
             "Juli":"July","August":"August","September":"September","Oktober":"October","November":"November",
             "Dezember":"December"}

# 优化循环顺序：遍历每个列表元素，匹配字典键做替换
for idx, item in enumerate(data):
    for de_month, en_month in dictionary.items():
        if de_month in item:
            data[idx] = item.replace(de_month, en_month)
            # 匹配到对应月份后即可跳出内层循环，避免无效遍历
            break

print(data)

运行修复后的代码，得到预期输出：

['18. September 2021', '7. June 1946', 'May 2021, 19', '16.9.2021']

内容的提问来源于stack exchange，提问作者Aniiya0978