How to Properly Sort Flutter List with numbers and alphabet - list

Question

I have a list in flutter which I want to sort like this
List<SearchUserResult> userSearchList = [
SearchUserResult(name: "Bright Isaac", age: 27, price: "10000"),
SearchUserResult(name: "Bright John", age: 7, price: "5000"),
SearchUserResult(name: "Phil Isaac", age: 20, price: "Negotiable"),
SearchUserResult(name: "Sunday", age: 16, price: "400")
];
What am trying to do is to get the highest price and the lowest price
userSearchList.sort((a, b) => a.price.compareTo(b.price)); //Get highest price
userSearchList.sort((b, a) => a.price.compareTo(b.price)); // Get lowest price
but I want that if am trying to get the lowest price it should be numbers like 10000 cause if you look at the list there is a Negotiable price and i don't want that to appear when sorting it only the numbers And also if you can help me i also want to be able sort it so that only the Negotiable without the numbers will show. Please how do i go about this.

Answer 1

Assuming you don't have the capability to do this on the server-side and just want to do this in client-side code, it shouldn't be too difficult.
If you really don't care about doing it in an optimal way, you could write something like this:
class PriceSearchUser {
num price;
SearchUserResult sur;
final PriceSearchUser(this.price, this.sur);
}
...
final priceSearchUsers = userSearchList
// create new list of price-UserSearchResult, with price in a sortable value (num)
.map((sur) => PriceSearchUser(num.tryParse(sur.price), sur))
// filter out any where the price wasn't able to be parsed into a number
.where((psu) => psu.price != null)
// make it in to a list so you can sort it
.toList();
final sortedSearchUserResults = priceSearchUsers
// sort that list! (note the double '.' - that makes it return
// the same object so that I can call the next function
..sort((a,b) => a.price.compareTo(b.price))
// get back to your original objects
.map((psu) => psu.sur)
// (optional) make it back into a list rather than an iterable
.toList();
If you're only doing this on a few users that should be adequate; if you're doing it on a whole bunch then you might want to think about optimizing or doing it in an isolate.
You can do something very similar with a "where" clause to get only the "Negotiable" prices.
However, as one of the comments mentioned, you should probably think about how exactly you do this. You say that you have a lot of code now but I guarantee you'll have more code later the next time this becomes a problem.
Also, this doesn't seem like a super-serious money app, but if it were you always need to be very careful about how you treat your monetary values. Doubles sometimes round to weird things! You could use something like this package.