9. Swift

  • 9.1. Swift tutorial

    Swift, an open source programming language that supports multiple programming paradigms and compilation, was...
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  • 9.2. Swift environment building

    Swift is an open source programming language for developing OS X and iOS applications. Before the formal deve...
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  • 9.3. Swift basic syntax

    In the previous chapter, we talked about how to create “Hello, World!” in the Swift language. program. Now let’s revie...
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  • 9.4. Swift data type

    When we program in any programming language, we need to use a variety of data types to store different information. ...
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  • 9.5. Swift variable

    A variable is an easy-to-use placeholder that refers to the computer’s memory address. Each variable in Swift...
    2023-12-08 01:10:06 UTC
  • 9.6. Swift optional type

    The optional (Optional) type of Swift, which is used to handle cases where values are missing. Optional means “there i...
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  • 9.7. Swift constant

    Once a constant is set, its value cannot be changed while the program is running. Constants can be any data t...
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  • 9.8. Swift literal quantity

    A literal quantity is a value such as a specific number, string, or Boolean value that can directly indicate its own t...
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  • 9.9. Swift operator

    An operator is a symbol that tells the compiler to perform a mathematical orlogical operation. Swift provides...
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  • 9.10. Swift conditional statement

    A conditional statement executes the program through one or more conditions set, executing the specified statement whe...
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  • 9.11. Swift if statement

    One if a statement consists of a Boolean expression followed by one or more statements. ...
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  • 9.12. Swift if…else statement

    One if statement can be followed by an optional else statement ...
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  • 9.13. Swift if…else if…else statement

    One if statement can be followed by an optional else if...
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  • 9.14. Swift nested if statement

    In the Swift language, you can use a if or else if ...
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  • 9.15. Swift switch statement

    The switch statement allows you to test when a variable is equal to multiplevalues. In the Swift language, as long as ...
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  • 9.16. Swift cycle

    Sometimes, we may need to execute the same piece of code multiple times. In general, statements are executed sequentia...
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  • 9.17. Swift for-in cycle

    Swift for-in loops are used to traverse all the elements in a collection, such as intervals ...
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  • 9.18. Swift for cycle

    This loop has been deprecated in Swift 3. Swift for a loop is used to repeat a seri...
    2023-12-08 01:10:06 UTC
  • 9.19. Swift While cycle

    Swift while the loop begins by calculating a single condition. If the condition is ...
    2023-12-11 00:54:58 UTC
  • 9.20. Swift repeat…while cycle

    Swift repeat...while the cycle is not like for and w...
    2023-12-08 01:10:06 UTC
  • 9.21. Swift Continue statement

    Swift continue statement tells a loop body to stop this loop iteration immediately and resta...
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  • 9.22. Swift Break statement

    Swift break statement immediately ends the execution of the entire control flow. If...
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  • 9.23. Swift Fallthrough statement

    Swift fallthrough statement let case subsequent statements continu...
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  • 9.24. Swift string

    A Swift string is a collection of characters. For example, “Hello, World!”a collection of values of such an ordered ch...
    2023-12-08 01:10:05 UTC
  • 9.25. Swift character

    The character of Swift is a single character string literal, and the data type is Character ...
    2023-12-08 01:10:06 UTC
  • 9.26. Swift array

    Swift arrays use ordered lists to store multiple values of the same type. The same value can appear multiple times in ...
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  • 9.27. Swift dictionary

    Swift dictionaries are used to store unordered collections of data of the same type. Swift dictionaries force the type...
    2023-12-11 00:54:57 UTC
  • 9.28. Swift function

    A separate block of code that the Swift function uses to accomplish a specific task. Swift uses a unified syn...
    2023-12-11 00:54:58 UTC
  • 9.29. Swift closure

    Closures are self-contained blocks of functional code that can beused in code or used as parameters to pass values. ...
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  • 9.30. Swift enumeration

    Enumeration is simply a data type, except that this data type contains only custom-specific data, which is a collectio...
    2023-12-08 01:10:06 UTC
  • 9.31. Swift structure

    The Swift structure is a general and flexible construct used to build code. We can extend the function of the...
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  • 9.32. Swift class

    The Swift class is a generic and flexible construct used to build code. We can define properties (constants, ...
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  • 9.33. Swift attribute

    The Swift property associates a value with a specific class, structure, or enumeration. Attributes can be div...
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  • 9.34. Swift method

    Swift methods are functions associated with certain types In Objective-C, a class is the only type that can d...
    2023-12-08 01:10:05 UTC
  • 9.36. Swift inheritance

    Inheritance can be understood as one class getting the methods and properties of another class. When a class ...
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  • 9.37. Swift construction process

    The construction process is a preparation process for using an instance of aclass, structure, or enumerated type. This...
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  • 9.38. Swift destructing process

    The destructor is called immediately before an instance of a class is released. Use keywords deinit ...
    2023-12-08 01:10:05 UTC
  • 9.39. Swift optional chain

    An optional chain is a process that can request and invoke properties, methods, and subscripts, and the target for a r...
    2023-12-08 01:10:05 UTC
  • 9.40. Swift automatic reference count (ARC)

    Swift uses automatic reference counting (ARC) to track and manage application memory Usually we don’t need to...
    2023-12-08 01:10:05 UTC
  • 9.41. Swift type conversion

    Swift language type conversion can determine the type of instance. It can also be used to detect whether an instance t...
    2023-12-11 00:54:57 UTC
Principles, Technologies, and Methods of Geographic Information Systems  102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.