Create nested dictionary where outer dictionary are column labels and inner dictionary are row label-CodePudding

I have a txt file:

:Dog : Cat or Lion : Dragon
Size : 10.2 : 20.2 : 30.5
Height : 5.4 : 10.4 : 20.7
Fat % : 0.35 : 0:20 : 0:10

I would like column labels (Dog, Cat or Lion, Dragon) as my outer dictionary.

Inner dictionary keys should be Size, Height

So if I run data['Dog'] ['Size)" 10 should be printed out and values in they inner dictionary to be strings.

I face issues with creating the inner dictionary keys...

CodePudding user response：

Here is how to do it (a bit more detailed explanation is in the other code example):

from collections import defaultdict

filename = 'myfile.txt'
with open(filename) as file:
    dct = defaultdict(dict)
    # get the first line which will be the headers
    _, *headers = file.readline().split(':')
    # iterate over the next lines
    for line in file:
        # split line by ':' to extract the row name and the data
        param, *data = line.split(':')
        # zip together headers with the data
        for animal, value in zip(headers, data):
            # add the values to the dictionary
            dct[animal.strip()][param.strip()] = value.strip()
    dct = dict(dct)

print(dct)

You can also use the built-in csv library like this:

import csv
from collections import defaultdict

file_name = 'myfile.txt'
with open(file_name, newline='') as file:
    # read the data in a dictionary iterable where it represents
    # each column name and its value in each row
    reader = csv.DictReader(file, delimiter=':')
    # create a defaultdict with the dictionary to make it easier
    # to create the inner dictionaries
    dct = defaultdict(dict)
    # iterate over rows
    for row in reader:
        # simple unpacking
        (_, param), *data = row.items()
        # you can
        # print(param, data)
        # to see what it all contains but you should understand from the names
        # iterate over the data and place the values in the dictionary
        # usage of defaultdict here allows to immediately use keys
        # for the inner dictionary
        for animal, value in data:
            dct[animal.strip()][param.strip()] = value.strip()
    # conver the dct to a normal dictionary
    dct = dict(dct)


print(dct)

CodePudding user response：

The logic is usually the hardest part of solving a programming problem. Here's the logic. You can write the code.

data = {} # empty dict
for each line in the file
    split the line by ":"
    strip leading and trailing white space from each split field
    if the first field is empty
        store the fields into a name_array
        for each subsequent field in the line
            use the field as the key of a new dict entry, where the value is an empty dict
    else
        use the first field as the_key
        for each subsequent field in the line
            get the field position (index)
            use the field position to extract the name from the name_array
            update data[name][the_key] = subsequent field

The above general logic should give you a workable solution to your program without having to use any external libraries/modules.