How can save the text of the label as an integer variable in swift?

I need to save the changing text of my label as a variable, but if write the following code:

var warn = Int(self.dyn.text)

It says:

Value of optional type 'String?' must be unwrapped to a value of type 'String'
Coalesce using '??' to provide a default when the optional value contains 'nil'
Force-unwrap using '!' to abort execution if the optional value contains 'nil'

What code should I use?

var warn = Int(self.dyn.text ?? "") ?? 0

You have to provide a default value, just in case it's not possible to make the cast to Int. You also have to make sure the text value is not nil.

Take a look at optional chaining and optional binding

Another approach is:

    if let dynText = self.dyn.text {
        if let warn = Int(dynText) {

            // warn is an available int variable here.
        }
    }