如何根据特定元素的存在对 python 字典进行切片

Question

I have dictionary like this:

mydictionary = {0: header,
1: thumbnail, 
2: paragraph, 
3: header, 
4: thumbnail,
5: thumbnail, 
6: paragraph, 
7: paragraph}

im looping through the dictionary and if I find a paragraph, I want to find all the previous thumbnails but only up to previous paragraph.

for x in mydictionary:
   if paragraph in mydictionary:
      find all the previous thumbnails up to previous paragraph

in other words at paragraph 2, it would return item 1

in paragraph 6, it would return item 4 and 5

in paragraph 7, nothing will be returned

Answer 1

You can do something like this:

mydictionary = {0: "header",
                1: "thumbnail", 
                2: "paragraph", 
                3: "header", 
                4: "thumbnail",
                5: "thumbnail", 
                6: "paragraph", 
                7: "paragraph"}

prev_thumbnails = []
for key, value in mydictionary.items():
    if value == "thumbnail":
        prev_thumbnails.append(key)
    elif value == "paragraph":
        print(prev_thumbnails)
        prev_thumbnails = []
#returns
#[1]
#[4, 5]
#[]