herb | Add some flavor to your Node CLI | Runtime Evironment library

You can replace your 0 values with NAs, for example with, dplyr::na_if(0) on your dataframe:

i'll also go with the your following statement:

2. A function is thread safe if it does not access any memory that could be modified without internal synchronization by another function. This seems to me the most consistent option, but is not the way it is often used.

As long as the shared variable is atomic and mutex are properly used to achieve synchronization, i don,t see any problem with your above statement.

&Animal is short for &dyn Animal. dyn Animal is a trait object type, and it only exists for a given trait if the trait is object-safe. Traits with associated types are not object-safe, because dyn Animal cannot implement Animal without specifying the associated type Food.¹

This is an inherent limitation of runtime polymorphism (trait objects): you don't know the concrete type, so you can't know its associated type.²

If you want to create a vector of things you can call .talk() on, it's easy enough to create a trait just for that (playground):

Because the object you're looking up with doesn't exist in the Dictionary.

You can convince yourself of this quite easily, just loop through the Keys collection and use == or Equals to compare each key dictionary to the searched-for dictionary.

That is

By default, newsapi shows 20 results per page. You can control that by using pageSize and page params.

Top headlines documentation

print(news); have limited output and will not print the entire map.

Use the following print statement to check how many object do you have in the articles list: print('Articles count: ${news['articles'].length}');

You need to change this code in order to get the item count:

Use render_to_hash instead of outputting each serializer as JSON

PlantName is not a "nested array". healthMonitor is an array that contains a single item, which is an object containing one field: PlantName.

Your update is not working as your data is string "3" but your update filter is on numeric 3.

If you want to update the PlantName field in the first element of the array, use:

First, you are creating 3 new entities and trying to Add, Update and Delete them. A new entity can be Added, but cannot be Updated or Deleted. Think about it, it is an object that you have just created, and it is not in the database yet. How do you expect to Update/Delete it? To Update or Delete an entity it must be an existing one.

Second, you are using newly created (without any Id) Address and Category objects to update myAdress and MyCategory properties. Those two are not primitive properties representing column values like the rest of them, they are related entities with foreign key constraints. If you really want to change/update them, you must set one that is already existing in database with Id. Otherwise, it will violate the foreign key constraint (or, referential integrity constraint), that's exactly is what the first error message is saying.

Try the following, for Update -