Split output to populate nested dictionary python

问题

I am trying to populate a nested dictionary, but are having trouble since I am fairly new to python (also to Stack Overflow).

I have a txt file with paths to photos and I would like to populate the splits from it to a nested dictionary. An example of the text file looks like this:

/photos/Bob_January_W1_001.png
/photos/Alice_April_W2_003.png

Where Bob is the user, January is the month, W1 the week and 001 the nr of the photo. Etc.

I would like to populate a nested dictionary in the following structure (based on what I have read):

{'Bob': {'January': {'W1': 001, 002, 003}, {'W2': 001, 002,003}}, 'February': {'W3': 001, 002}}  #And so on for other keys as well

So far I have only managed to sort the numbers to a user, like this:

sorteddict = {}
with open('validation_labels.txt','r') as f:
    for line in f:
        split = line.split('_')
        user = split[1]
        month = split[2]
        week = split[3]
        image = split[4]

        if action_class in clipframe:
            sorteddict[user].append(image)
        else:
            sorteddict[user] = [image]

But now I want the nested structure I described. I started by initializing my nested dict, like this nesteddict[user][month][week].append(image), but I recieve KeyError: 'Bob'. I also understand that I am going to need a lot more if statements and conditions. But I don't know where to begin.

回答1:

You can use nested sets of collections.defaultdict to build your data:

from collections import defaultdict

dct = defaultdict(lambda: defaultdict(lambda: defaultdict(list)))

with open('validation_labels.txt','r') as f:
    for line in f:
        line = line.strip('/photo/')
        user, month, week, image = line.split('_')
        dct[user][month][week].append(image)

回答2:

I have done something like this before:

temp = sorteddict
for key in keys[:-1]:
    if key not in temp:
        temp[key] = {}
    temp = temp[key]
temp[keys[-1]] = value

So, your keys would need to be in a list (the keys list) and the value that you want at the end of that key chain is in value

来源：https://stackoverflow.com/questions/43234439/split-output-to-populate-nested-dictionary-python

标签

python

dictionary

text-files