Kotlin - Idiomatic way to check array contains value
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Kotlin - Idiomatic way to check array contains value
What's a idiomatic way to check if an array of strings contains a value in kotlin? Just like ruby's #include?.
#include?
I though about:
array.filter { it == "value" }.any()
Is there a better way?
Considering the upvotes in the answers, in 2 days I guess i helped 18 people and got 60 views. I think it's positive for the community and no question is too dumb to be asked.
– jturolla
Feb 16 '17 at 10:56
4 Answers
4
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.
in
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)
– Adam Hurwitz
Aug 3 '17 at 1:30
Just write var domainFound = domainsArray.contains(email) or more idiomatic var domainFound = email in domainsArray
– Geoffrey Marizy
Aug 3 '17 at 13:49
You can use the in operator which, in this case, calls contains:
in
contains
"value" in array
"value" in array
Using in operator is an idiomatic way to do that.
val contains = "a" in arrayOf("a", "b", "c")
You could also check if the array contains an object with some specific field to compare with using any()
any()
listOfObjects.any{ object -> object.fieldxyz == value_to_compare_here }
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Why would you post this kind of questions on stackoverflow? Just google it or open API reference.
– Murat Mustafin
Feb 16 '17 at 5:07