How to check to see if a string is a decimal number in Scala

Solution 1:

Try this:

def isAllDigits(x: String) = x forall Character.isDigit

forall takes a function (in this case Character.isDigit) that takes an argument that is of the type of the elements of the collection and returns a Boolean; it returns true if the function returns true for all elements in the collection, and false otherwise.

Solution 2:

Do you want to know if the string is an integer? Then .toInt it and catch the exception. Do you instead want to know if the string is all digits? Then ask one of:

s.forall(_.isDigit)
s matches """\d+"""