Parsing a String That's Kind of JSON - json

Question

I have a set of strings that's JSONish, but totally JSON uncompliant. It's also kind of CSV, but values themselves sometimes have commas.
The strings look like this:
ATTRIBUTE: Value of this attribute, ATTRIBUTE2: Another value, but this one has a comma in it, ATTRIBUTE3:, another value...
The only two patterns I can see that would mostly work are that the attribute names are in caps and followed by a : and space. After the first attribute, the pattern is , name-in-caps : space.
The data is stored in Redshift, so I was going to see if I can use regex to resolved this, but my regex knowledge is limited - where would I start?
If not, I'll resort to python hacking.

Answer 1

What you're describing would be something like:
^([A-Z\d]+?): (.*?), ([A-Z\d]+?): (.*?), ([A-Z\d]+?): (.*)$
Though this answer would imply your third attribute value doesn't really start with a comma, and that your attributes name could countain numbers.
If we take this appart:
[A-Z\d] Capital letters and numbers
+?: As many as needed, up to the first :
(.*?), a space, then as many characters as needed up to a coma and a space
^ and $ The begining and the end of a string, respectively
And the rest is a repetition of that pattern.
The ( ) are just meant to identify your capture sections, in this case, they don't impact directly the match.
Here's a working example

Answer 2

Often regex is not the right tool to use when it seems like it is.
Read this thoughtful post for details: https://softwareengineering.stackexchange.com/questions/223634/what-is-meant-by-now-you-have-two-problems
When a simpler scheme will do, use it! Here is one scheme that would successfully parse the structure as long as colons only occur between attributes and values, and not in them:
Code
static void Main(string[] args)
{
string data = "ATTRIBUTE: Value of this attribute,ATTRIBUTE2: Another value, but this one has a comma in it,ATTRIBUTE3:, another value,value1,ATTRIBUTE4:end of file";
Console.WriteLine();
Console.WriteLine("As an String");
Console.WriteLine();
Console.WriteLine(data);
string[] arr = data.Split(new[] { ":" }, StringSplitOptions.None);
Dictionary<string, string> attributeNameToValue = new Dictionary<string, string>();
Console.WriteLine();
Console.WriteLine("As an Array Split on ':'");
Console.WriteLine();
Console.WriteLine("{\"" + String.Join("\",\"", arr) + "\"}");
string currentAttribute = null;
string currentValue = null;
for (int i = 0; i < arr.Length; i++)
{
if (i == 0)
{
// The first element only has the first attribute name
currentAttribute = arr[i].Trim();
}
else if (i == arr.Length - 1)
{
// The last element only has the final value
attributeNameToValue[currentAttribute] = arr[i].Trim();
}
else
{
int indexOfLastComma = arr[i].LastIndexOf(",");
currentValue = arr[i].Substring(0, indexOfLastComma).Trim();
string nextAttribute = arr[i].Substring(indexOfLastComma + 1).Trim();
attributeNameToValue[currentAttribute] = currentValue;
currentAttribute = nextAttribute;
}
}
Console.WriteLine();
Console.WriteLine("As a Dictionary");
Console.WriteLine();
foreach (string key in attributeNameToValue.Keys)
{
Console.WriteLine(key + " : " + attributeNameToValue[key]);
}
}
Output:
As an String
ATTRIBUTE: Value of this attribute,ATTRIBUTE2: Another value, but this one has a comma in it,ATTRIBUTE3:, another value,value1,ATTRIBUTE4:end of file
As an Array Split on ':'
{"ATTRIBUTE"," Value of this attribute,ATTRIBUTE2"," Another value, but this one has a comma in it,ATTRIBUTE3",", another value,value1,ATTRIBUTE4","end of file"}
As a Dictionary
ATTRIBUTE : Value of this attribute
ATTRIBUTE2 : Another value, but this one has a comma in it
ATTRIBUTE3 : , another value,value1
ATTRIBUTE4 : end of file