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I notice that List class define the method ::, which adds an element at the beginning of the list
def ::(x: A): List[A]
Example:
1 :: List(2, 3) = List(2, 3).::(1) = List(1, 2, 3)
However, I am confused at How does scala compiler recognize such conversion? Because as far as I am concerned,
1 :: List(2,3)
should raise an error: :: is not a member of Int
Do I miss something about operator definition of scala?
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contains() function in Scala is used to check if a list contains the specific element sent as a parameter. list. contains() returns true if the list contains that element. Otherwise, it returns false .
Scala List Methods. head: This method returns the first element of the scala list. tail: This method returns all the elements except the first. isEmpty: This method checks if the list is empty in which case it returns True else False.
tail: This method returns a list consisting of all elements except the first.
This is the first method we use to append Scala List using the operator “:+”. The syntax we use in this method is; first to declare the list name and then use the ':+' method rather than the new element that will be appended in the list. The syntax looks like “List name:+ new elements”.
Methods whose names end with : are right-associative when called using infix operator notation. I.e.
a foo_: b
is the same as
b.foo_:(a)
This rule exists specifically for the case of methods like this, which are commonly (in other languages such as Haskell and ML) operators like : or ::.
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