在Python中将字典值动态初始化为零

Question

I am assigning the dictionary keys on the fly after detecting what language a predicted string belongs to and I was wondering how to initialize it to zero.

from textblob import TextBlob


correct = {}     

    for i in max_dist_indices:          
...
        correct[TextBlob(predicted_labels[j]).detect_language()] += 1*(predicted_labels[i] == labels[i])

Where d etect.language() returns a string according to the language in the predicted labels, ' en ' for English, which serves as the key. Any ideas how this could be done?

Answer 1

You can use the dict.get method:

language = TextBlob(predicted_labels[j]).detect_language()
correct[language] = correct.get(language, 0) + (predicted_labels[i] == labels[i])

or you can initialize correct as defaultdict(int) instead:

from collections import defaultdict
correct = defaultdict(int)
correct[language] += predicted_labels[i] == labels[i]

Answer 2

With dictionaries, you have key-value pairs. When you say you want to initialise a key to 0, I think you mean you want to initialise its value to 0.

Assuming that 1*(predicted_labels[i] is not equal to labels[i]) and will therefore return 0, the following should give what you want:

correct[TextBlob(predicted_labels[j]).detect_language()] = 1*(predicted_labels[i] == labels[i])