Rust By Example: Iterator Any
"Annie" is a function in Rust language that works in combination with another function. It's related to closure concepts you might have studied. Annie is an in-built function in Rust.
Basically, this function is employed along with an iterator and will return "true" if any of the elements meet the prespecified conditions. If no element does, it gives back "false." It's a binary-type function, meaning it only gives a "true" or "false" output. You can use it to check if any elements in a list, vector, array or a tuple satisfy certain prerequisites.
Consider having an array of numbers like 1, 2, 3. Apply "Annie" along with a closure, and check if any of the data match your conditions, let's say for example "x equals 2". If it returns ‘true’, that means the condition was met.
So, it’s similar to conducting a search, only difference being the return is about presence or absence of the element only. I find this pretty slick. You can validate your input data or check if certain fields are present within an iterator.
It can be a handy tool for ensuring all necessary conditions are met. There are different ways to script an iterator. If you have a vector called "vec1" having 1, 2, 3, you can use "vec1.iteratorAnnie" and then destructure it with a reference to the data.
Alternatively, you can use "into_iterator" which requires no destructuring, for a simpler syntax. In a closure, the double pipe serves to denote parameters passed into, followed by the start and end of your closure. One of the cool things about Rust language is that while creating closure, it requires only essential syntax ensuring brevity.
Although complex use-cases with multiple lines should ideally utilize a predefined function situated higher up in your code, saving the need for closure. The Annie function is super helpful. If any item in your list fits the bill, it will return ‘true’.
If not, it’s a ‘false'. The function is readily available on Rust.
