1、创建一个列表lst，添加一些元素，代码如下：lst = ["ab","acd","ef","jhi","gk"]
3、用for循环提取所有lst列表中的元素，为做判断准备，具体代码如下：for el in lst:
5、运行代码测试后，实现了过滤和大写的转换整体代码总结：lst = ["ab","acd","ef","jhi"稆糨孝汶;,"gk"]new_lst=[]for el in lst: if len(lst)>3: new_lst.append(el.upper())print(new_lst)
7、总结两种方法：方法一代码量比较多，但是在程序报错的时候容易发现方法二代码量少，缺点是在出问题的时候不容易发现方法一整体代码：lst = ["ab","acd","ef","jhi","gk"]new_lst=[]for el in lst: if len(lst)>3: new_lst.append(el.upper())print(new_lst)方法二整体代码：lst = ["ab","acd","ef","jhi","gk"]new_lst = [el.upper() for el in lst if len(lst) > 3]print(new_lst)
