9. Swift

  • 9.18. Swift for cycle

    This loop has been deprecated in Swift 3. Swift for a loop is used to repeat a series of statements until a specific c...
    2025-10-25 13:33:48 UTC
  • 9.19. Swift While cycle

    Swift while the loop begins by calculating a single condition. If the condition is true will run a series of stateme...
    2025-10-25 13:33:47 UTC
  • 9.20. Swift repeat…while cycle

    Swift repeat...while the cycle is not like for and while the loop judges the conditional statement before the lo...
    2025-10-25 13:33:45 UTC
  • 9.21. Swift Continue statement

    Swift continue statement tells a loop body to stop this loop iteration immediately and restart the next loop iteration. ...
    2025-10-25 13:33:50 UTC
  • 9.22. Swift Break statement

    Swift break statement immediately ends the execution of the entire control flow. If you are using a nested loop (that ...
    2025-10-25 13:33:52 UTC
  • 9.23. Swift Fallthrough statement

    Swift fallthrough statement let case subsequent statements continue to run sequentially, regardless of whether the c...
    2025-10-25 13:33:47 UTC
  • 9.24. Swift string

    A Swift string is a collection of characters. For example, “Hello, World!”a collection of values of such an ordered characte...
    2025-10-25 13:33:51 UTC
  • 9.25. Swift character

    The character of Swift is a single character string literal, and the data type is Character . The following example li...
    2025-10-25 13:33:48 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 differ...
    2025-10-25 13:33:44 UTC
  • 9.27. Swift dictionary

    Swift dictionaries are used to store unordered collections of data of the same type. Swift dictionaries force the type of el...
    2025-10-25 13:33:45 UTC
  • 9.28. Swift function

    A separate block of code that the Swift function uses to accomplish a specific task. Swift uses a unified syntax to repres...
    2025-10-25 13:33:46 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. Closur...
    2025-10-25 13:33:48 UTC
  • 9.30. Swift enumeration

    Enumeration is simply a data type, except that this data type contains only custom-specific data, which is a collection of d...
    2025-10-25 13:33:48 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 structure by...
    2025-10-25 13:33:48 UTC
  • 9.32. Swift class

    The Swift class is a generic and flexible construct used to build code. We can define properties (constants, variables) an...
    2025-10-25 13:33:44 UTC
  • 9.33. Swift attribute

    The Swift property associates a value with a specific class, structure, or enumeration. Attributes can be divided into sto...
    2025-10-25 13:33:46 UTC
《地理信息系统原理、技术与方法》  97

最近几年来,地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持,如城市管理、区划、环境整治等等,地理信息成为信息时代重要的组成部分之一; “数字地球”概念的提出,更进一步推动了作为其技术支撑的GIS的发展。 与此同时,一些学者致力于相关的理论研究,如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面,并且这两个方面构成了相互促进的发展过程。