Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "We just need to enter :help to list all the available debugger commands."

A block of code is set as follows:

    let degCUnit = HKUnit.degreeCelsius() 
    let degFUnit = HKUnit.degreeFahrenheit()

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

    open func filteredBy(condition: (Int) -> Bool) -> [Int] { 
      return numbersList.filter({ condition($0) }) 
    }

Any command-line input or output is written as follows:

id: 1, name: "Invaders 2017", highestScore: 1050, playedCount: 3050

id: 2, name: "Minecraft", highestScore: 3741050, playedCount: 780009992

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Clicking the Next button moves you to the next screen."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.