Extracting information between two curly brackets in a file with Python

Question

I have a file that was written in a JSON structure but is not correctly formatted. The content looks similar to this:

[{"key0":"value0" , "key1":"value1", "key2":"value2"}, {"key0":"value3", "key1":"value4", "key2:"value5"}, {"key0":"value6", "key1":"value7", "key2:"value8"}]

Unlike many questioned asked here before, the contents are all on the same line, so I was trying to read the code line by line but I select the whole thing if I use readline().

I am trying to extract only the information between the curly brackets { } with the brackets, and print them. I am able to open the file, but I am finding it difficult to find a way to read starting from the { and ending at } then continue to look for the next { and } and so on. I don't really care about the square brackets, just the curly brackets. Also, the values can differ in length so I can set a number of characters to be read after the bracket, as it is different for each set of brackets most of the time.

Any guidance would be greatly appreciated.

Answer 1

import re

fileContent = "[{'key0':'value0' , 'key1':'value1', 'key2':'value2'}, {'key0':'value3', 'key1':'value4', 'key2':'value5'}, {'key0':'value6', 'key1':'value7', 'key2':'value8'}]"

pattern_with_braces = r'\{.*?\}'
pattern_without_braces = r'(?<=\{).*?(?=\})'
parts = re.findall(pattern_without_braces, fileContent)

Answer 2

I suggest you use the regex module in order to modify the lines and then transform them into a dictionary:

import re
import json
with open("data.txt") as f:
  lines = f.readlines()
  for line in lines:
    modified = re.sub(r"({|\s)\"(\w+):", r'\1"\2":', line)
    dictionary = json.loads(modified)
    print(dictionary)

In your example, running the code above would result in something like:

[{'key0': 'value0', 'key1': 'value1', 'key2': 'value2'}, {'key0': 'value3', 'key1': 'value4', 'key2': 'value5'}, {'key0': 'value6', 'key1': 'value7', 'key2': 'value8'}]

Moreover, you will have access to the keys and values of this dictionary.

Note that the "data.txt" file in the code above is as follows:

[{"key0":"value0" , "key1":"value1", "key2":"value2"}, {"key0":"value3", "key1":"value4", "key2:"value5"}, {"key0":"value6", "key1":"value7", "key2:"value8"}]

Answer 3

Try using json.loads method from Python json encoder module that "Deserialize fp (a.read()-supporting text file or binary file containing a JSON document) to a Python object using a conversion table".

To decode your json string:

import json

str_to_load = '[{"key0":"value0" , "key1":"value1", "key2":"value2"}, {"key0":"value3", "key1":"value4", "key2":"value5"}, {"key0":"value6", "key1":"value7", "key2:"value8"}]'
str_to_load = json.loads(str_to_load)

print(str_to_load[2]['key2'])

output: value8