Python-将文本文件转换为dict并转换为json

Question

How can I convert this text file to json? Ultimately, I'll be inserting the json blobs into a NoSQL database, but for now I plan to parse the text files and build a python dict, then dump to json.

I think there has to be a way to do this with a dict comprehension that I'm just not seeing/following (I'm new to python).

Example of a file:

file_1.txt
[namespace1] => metric_A = value1
[namespace1] => metric_B = value2
[namespace2] => metric_A = value3
[namespace2] => metric_B = value4
[namespace2] => metric_B = value5

Example of dict I want to build to convert to json:

{  "file1" : {
             "namespace1" : {
                 "metric_A" : "value_1",
                 "metric_B" : "value_2"     
             },
             "namespace2" : {
                 "metric_A" : "value_3",
                 "metric_B" : ["value4", "value5"]
             }
}

I currently have this working, but my code is a total mess (and much more complex than this example w/ clean up etc). I'm basically going line by line through the file, building a python dict. I check each namespace for existence in the dict, if it exists, i check the metric. If the metric exists already, I know I have duplicates and need to convert the value to an array that contains the existing value and my new value(s). There has to be a more simple/clean way.

Answer 1

import glob
import json

answer = {}
for fname in glob.glob(file_*.txt):  # loop over all filenames
    answer[fname] = {}
    with open(fname) as infile:
        for line in infile:
            line = line.strip()
            if not line: continue
            splits = line.split()[::2]
            splits[0] = splits[0][1:-1]
            namespace, metric, value = splits  # all the values in the line that we're interested in
            answer[fname].get(namespace, {})[metric] = value  # populate the dict

required_json = json.dumps(answer)  # turn the dict into proper JSON

Answer 2

You can use regex for that. re.findall('\\w+', line) will find all text groups which you are after, then the rest is saving it in the dictionary of dictionary. The simplest way to do that is to use defaultdict from collections .

import re

from collections import defaultdict

answer = defaultdict(lambda: defaultdict(lambda: []))

with open('file_1.txt', 'r') as f:
    for line in f:
        namespace, metric, value = re.findall(r'\w+', line)
        answer[namespace][metric].append(value)

As we know, that we expect exactly 3 alphanum groups, we assign it to 3 variable, ie namespace, metric, value . Finally, defaultdict will return defaultdict for the case when we see namespace first time, and the inner defaultdict will return an empty array for first append, making code more compact.