如何检查字典中的每个条目在 python 中是否为空？

Question

When trying to iterate over a dictionary, I tried to make sure that each value in the dictionary is not None or empty and an error is thrown. The code is bellow.

articleSummaries = {}
for techUrlDictionary in [newYorkTimesTechArticles, washingtonPostTechArticles]:
    for articleUrl in techUrlDictionary:
        if techUrlDictionary[articleUrl][0] is not None:
            if len(techUrlDictionary[articleUrl][0]) > 0:
                fs = FrequencySummarizer()
                summary = fs.extractFeatures(techUrlDictionary[articleUrl],25)
                articleSummaries[articleUrl] = {'feature-vector': summary,
                                               'label': 'Tech'}

And the error message looks like this.

----> 5         if techUrlDictionary[articleUrl][0] is not None:
      6             if len(techUrlDictionary[articleUrl][0]) > 0:
      7                 fs = FrequencySummarizer()

TypeError: tuple indices must be integers or slices, not dict

What would be the best way to execute these checks? So this error is avoided?

Answer 1

I can't run your code, and the wording of your question is a little ambiguous. As @Zvone said, you're using the url as a dictionary.

However, are you trying to do something similar like this?

articleSummaries = {}
for techUrlDictionary in [newYorkTimesTechArticles, washingtonPostTechArticles]:
    for articleUrl in techUrlDictionary:
        if techUrlDictionary[articleUrl][0]:
            if len(techUrlDictionary[articleUrl][0]) > 0:
                fs = FrequencySummarizer()
                summary = fs.extractFeatures(techUrlDictionary[articleUrl],25)
                articleSummaries[articleUrl] = {'feature-vector': summary,
                                               'label': 'Tech'}
        else:
            print("Empty entry") 

Answer 2

I'm assuming that each dict in the list has a key 0 . Since you are iterating through the list with the dict s, you can access the dict s as is:

articleSummaries = {}
for techUrlDictionary in [newYorkTimesTechArticles, washingtonPostTechArticles]:
    for articleUrl in techUrlDictionary:
        if articleUrl[0] is not None:
            if len(articleUrl[0]) > 0:
                fs = FrequencySummarizer()
                summary = fs.extractFeatures(articleUrl,25)
                articleUrl = {'feature-vector': summary,
                              'label': 'Tech'}