representer | web project , there is a high chance | Application Framework library

First of all you really shouldn't be using the old API anymore, there has been a new one, which allows much more control over what you are doing for several years now.

Second, you cannot put something that looks like a tag inside a string and not get quotes, during loading that would load like a tag and you might want that, but that would make an infinite number of strings (all those starting with !) non-representable in YAML.

If you don't know where to start, the thing to do is try and round-trip (load then dump) your required result:

I see two possible solutions.

The easiest solution is to use typ='safe' instead of typ='rt'. This is what I generally do , but if you're relying on ruamel.yaml's ability to preserve things like comments, this isn't an option.

You can create a representer for None values like this:

There is no built-in functionality to do what you want. Any time you encounter an alias, you would have to create a node structure in the composer recursively instead of just returning the anchor node for the alias.

The need for anchors and aliases in YAML documents arises from the need to be able to represent recursive data structures:

First of all, I don't think the output you present is complete, as it is invalid YAML and I certainly hope ruamel.yaml did not generate that as shown (if it did file a bug report with the complete source).

I don't know where you got that example from but the method ignore_aliases() is called with a data structure and should return True if any aliases should be ignored. It is not something you call yourself. You can subclass the Representer or monkey-patch that on the RoundTripRepresenter.

The method in representer.py should take a data parameter and always return False:

Solved! I used pandas to make DataFrame then into pivot table, then send it through context to my template. Also Taking the year of the report through the url that it's written by user. here's my views.py :

The best approach to keep an AWS ACM SSL whilst removing your load balancer would be to instead use CloudFront for your EC2 host.

If this is a different domain to your existing CloudFront distribution, you would need to create a new one which will serve your app traffic. This would have a custom origin that would resolve to the public CNAME of the EC2 host (this will require the EC2 host to be publicly resolvable).

IF it shares the same domain, your CloudFront distribution would need to be updated to include a secondary behaviour that maps to your EC2 hosts public hostname.

Please note for this option your instance must be public, this means that it is possibly to bypass CloudFront to perform this option. If you do not have a valid SSL on this EC2 host you will need to configure the CloudFront distribution to speak to the origin using HTTP.

An alternative (or combined option) would be to use a service such as certbot that can generate a valid SSL for your domain. This will ensure any public ingress to the instance can be encrypted securely over HTTPS.

The output of the"safe" mode is what PyYAML, from which ruamel.yaml was orginally derived, gives by default, the "leaf collections" are in flow-style. That is more compact, than the all-block-style output of the default (typ="rt"), which doesn't always increase readability. Especially in low numbers of total items (so the total fits in a window), or when the leaf collections have many items (and they wrap over multiple lines).

So the reason why round-trip defaults to all-block-style is because I agree that it looks nicer. Of course when round-trip is used for its intended purpose, the original style of each collection is preserved.

The difference is caused by the default_flow_style attribute on the YAML() instance set to None for "safe" mode and to False for "rt" mode:

In PyYAML 4.x, dump is an alias for safe_dump, which won't handle arbitrary objects:

Although the words "correct YAML" are not really accurate, and would be better phrased as "YAML output looking like you want it, except for the tag information", this fortunately gives some information on how you want your YAML to look, as there are an infinite number of ways to dump objects.

If you dump an object using ruamel.yaml: