How to Call a Function with no Parameter Labels in Swift?

Swift – Call Function with no Parameter Labels

To call a function with no parameter labels in Swift, place an underscore before that parameter in the function definition.

Examples

In the following program, we will define a function that accepts a String name, and specify this parameter name such that the label name is not required while calling the function.

main.swift

func greet(_ name: String) {
    print("Hello \(name)")
}

greet("Abc")

Output

If there are multiple parameters for a function, and if we would like only some of these parameters to be passed via function call without the need to mention the labels, place underscore only for these parameters.

main.swift

func greet(_ name: String, country: String) {
    print("Hello \(name)")
    print("Are you from \(country)?")
}

greet("Abc", country: "Canada")

Output

Conclusion

In this Swift Tutorial, we learned how to define a function in Swift such that no label is required to specify for a parameter while calling the function.