How can I check if an array of strings contains a value in Kotlin? Just like ruby's #include?.
I thought about:
array.filter { it == "value" }.any()
Is there another way?
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7 Answers
The equivalent you are looking for is the contains operator.
array.contains("value")
Kotlin offer an alternative infix notation for this operator:
"value" in array
It's the same function called behind the scene, but since infix notation isn't found in Java we could say that in is the most idiomatic way.
4 Comments
adamhurwitz.eth
When I try this in Kotlin I get a "Type inference failed. The value of the type parameter T should be mentioned in the input Types." private var domainsArray = arrayOf("@ebay.com", "@google.com", "@gmail.com", "@umd.edu") var domainFound = Arrays.asList(domainsArray).contains(email)
Geoffrey Marizy
Just write var domainFound = domainsArray.contains(email) or more idiomatic var domainFound = email in domainsArray
Viks
Any idea how to compare with ignorecase string? array.contains("value") do not check ignorecase for string.
Geoffrey Marizy
You could map array with the toLowerCase String extension function before calling contains.
You could also check if the array contains an object with some specific field to compare with using any()
listOfObjects.any{ obj -> obj.fieldxyz == value_to_compare_here }
Comments
Here is code where you can find specific field in ArrayList with objects. The answer of Amar Jain helped me:
listOfObjects.any{ it.field == "value"}
Comments
Using in operator is an idiomatic way to do that.
val contains = "a" in arrayOf("a", "b", "c")
Comments
You can use the in operator which, in this case, calls contains:
"value" in array
Comments
You can use it..contains(" ")
data class Animal (val name:String)
val animals = listOf(Animal("Lion"), Animal("Elephant"), Animal("Tiger"))
println(animals.filter { it.name.contains("n") }.toString())
output will be
[Animal(name=Lion), Animal(name=Elephant)]
Comments
You can use find method, that returns the first element matching the given [predicate], or null if no such element was found.
Try this code to find value in array of objects
val findedElement = array?.find {
it.id == value.id
}
if (findedElement != null) {
//your code here
}
2 Comments
Aan
How can you get the position of findedElement value from array?
L.Petrosyan
@AnzyShQ you can find a position with a methods
array.indexIf(Object o) -> will return you index of first founded element, array.lastIndexOf(Object o) -> will return you index of last founded element. You can also use predicate too, etc array.indexOfLast { it.name == "test " } or array.indexOfFirst { it.name == "test "}