Swift programming language is a powerful and intuitive tool designed by Apple for iOS, macOS, and more. One common mathematical conversion you might deal with in Swift, or any other programming language for that matter, is converting radians to degrees. It is a straightforward conversion, but can be a stumbling block for new coders. In mathematics, the degree is a measurement of a plane angle, defined so that a full rotation is 360 degrees. Radian is a unit of measurement of angles used widely in mathematics and physics, where one radian is the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle. As a developer, you would have to encounter the task of converting radians to degrees when working on development projects involving calculative functions. But fear not, creating a function to convert radians to degrees in Swift is simple and straightforward.

## Conversion From Radians To Degrees in Swift

The conversion from radians to degrees is not a complex process. It is based on the mathematical expression:

let degrees = radians * (180 / pi)

The `pi` acts as the constant in this case and is defined as `let pi = 3.14159265358979323846`. Now that we know the formula to calculate degrees from radians, you can generate a function in Swift that accomplishes this.

## Implementing The Conversion in Swift Code

Let’s start by creating our function. We’ll name it `radiansToDegrees`, it will receive the radians as a parameter and will return a Double representing the degrees. Here’s how you can do that in Swift:

func radiansToDegrees(radians: Double) -> Double { let degrees = radians * (180 / pi) return degrees }

## Understanding The Swift Code

Let’s delve into what the above code does. The function `radiansToDegrees` is defined which takes a single argument, `radians` of type Double.

Next, a new constant variable `degrees` is defined and set to the result of the expression, which is the argument `radians` multiplied by `(180/pi)`. This formula is the very basis for converting radians to degrees.

Finally, the function returns the value of `degrees` which is now the original input in its equivalent degree value.

## Swift Programming and Radian-Degree Conversion

To illustrate the usefulness of this, let’s imagine that we have a physics simulation program. Frequently in such programs, angles are stored in radians, as it’s the standard unit of angular measurement in physics.

However, if the end user of this application is to input or receive output about these angles, it may be more intuitive to work with degrees, as it’s the everyday unit we are accustomed to using in measuring and thinking about angles.. Hence, our `radiansToDegrees` function would play a pivotal role in such situations, neatly encapsulating the radian-degree conversion in a ready-to-use function, and aiding in delivering a user-friendly experience.

Understanding such simple but essential functions contributes significantly to mastering the Swift programming language and allows for clean and efficient code writing in the sphere of calculative functionalities. In conclusion, a good understanding of both simple and complex mathematical conversions is a must for any ambitious Swift developer.