I'm trying to find a value in a list of objects in kotlin, using for it "filter", but I need to return true or false if the value is found, but filter returns me a list of object in the case of match.
t.filter { it.retailerId == value }
？当我在对象列表中找到这个值时，如何返回布尔值？
If you need that the element is exactly one:
t.filter { it.retailerId == value }.size == 1
if not:
t.any { it.retailerId == value }
With foldRight and a break when you found it:
t.foldRight(false) {val, res ->
if(it.retailerId == value) {
return@foldRight true
} else {
res
}
}