How to read yaml without serialization

[JWJUN233233]

i wonder how to know if there is a key in yaml.
i wonder how to read a list directly.

[EdwardCooke]

You can use the parser to read the yaml quick and dirty to check if a key exists and interact with a list directly. Here's a quick example. Lists are more complicated, but not by much.

using YamlDotNet.Core;
using YamlDotNet.Core.Events;
var listLevel = 0;
string? lastScalar = null;

var yaml = @"
a: b
c: d
e: f
list1:
- list1 item 1 (just a simple scalar)
- list1 item 2 (it's a list in a list):
  - nested list for list 1
list2:
- list2 item 2 (it's a list in a list):
  - nested list for list 2
";

var parser = new Parser(new StringReader(yaml));
while (parser.MoveNext())
{
    var token = parser.Current;
    if (token is Scalar scalar)
    {
        lastScalar = scalar.Value;
        if (scalar.IsKey)
        {
            if (scalar.Value == "c")
            {
                Console.WriteLine("c key exists");
            }
            if (scalar.Value == "d")
            {
                Console.WriteLine("d matched but shouldn't");
            }
        }
    }
    else if (token is SequenceStart start)
    {
        listLevel += start.NestingIncrease;
        Console.WriteLine("we're starting a list that was keyed as {0}. New level: {1}", lastScalar, listLevel);
    }
    else if (token is SequenceEnd end)
    {
        listLevel += end.NestingIncrease;
        Console.WriteLine("End of list. New level: {0}", listLevel);
    }
}

Results in:

c key exists
we're starting a list that was keyed as list1. New level: 1
we're starting a list that was keyed as list1 item 2 (it's a list in a list). New level: 2
End of list. New level: 1
End of list. New level: 0
we're starting a list that was keyed as list2. New level: 1
we're starting a list that was keyed as list2 item 2 (it's a list in a list). New level: 2
End of list. New level: 1
End of list. New level: 0

Does this help?