6. Ruby

  • 6.19. Ruby block

    You already know how Ruby defines methods and how you call them. Similarly, Ruby has the concept of a block. Blocks are ...
    2025-10-25 13:34:02 UTC
  • 6.20. Ruby module

    A Module is a way of combining methods, classes, and constants. Modules provide you with two major benefits. The module ...
    2025-10-25 13:34:05 UTC
  • 6.21. Ruby string

    The String object in Ruby is used to store or manipulate a sequence of one or more bytes. Ruby strings are divided into si...
    2025-10-25 13:34:01 UTC
  • 6.22. Ruby array

    The Ruby array is an ordered integer index collection of any object. Each element in the array is associated with an index a...
    2025-10-25 13:33:58 UTC
  • 6.23. Ruby hash

    Hash is similar "key" => "value" such a collection of key-value pairs. A hash is similar to an array, except that...
    2025-10-25 13:34:01 UTC
  • 6.24. Ruby date & time

    The Time class is used in Ruby to represent the date and time. It is based on the system date and time provided by the opera...
    2025-10-25 13:33:59 UTC
  • 6.25. Ruby range

    Ranges (Range) are everywhere: a to z, 0 to 9, and so on. Ruby supports scope and allows us to use scope in different ways: ...
    2025-10-25 13:34:01 UTC
  • 6.26. Ruby iterator

    To put it simply: iterate means doing the same thing over and over again, sothe iterator is used to repeat the same thing ma...
    2025-10-25 13:34:04 UTC
  • 6.27. Input and output of Ruby files

    Ruby provides a complete set of Istroke O-related methods, implemented in kernel (Kernel) modules. All the Icano methods are...
    2025-10-25 13:34:05 UTC
  • 6.28. Ruby File classes and methods

    File represents a connection to a normal file stdio object. open returns an instance of this class for a normal ...
    2025-10-25 13:34:03 UTC
  • 6.29. Ruby Dir classes and methods

    Dir is a directory stream that represents a file name in a directory in the operating system. Dir classes also have ...
    2025-10-25 13:34:02 UTC
  • 6.30. Ruby exception

    Exceptions and execution are always associated. If you open a file that does not exist and do not handle the situation prope...
    2025-10-25 13:33:58 UTC
  • 6.31. Ruby object oriented

    Ruby is a pure object-oriented language, and everything in Ruby appears in the form of objects. Every value in Ruby is an ob...
    2025-10-25 13:34:00 UTC
  • 6.33. Ruby Database access-DBI tutorial

    This section will show you how to access a database using Ruby. Ruby DBI The module provides a database-independent interf...
    2025-10-25 13:33:57 UTC
  • 6.34. Ruby DBI Read operation

    DBI provides several different ways to get records from a database. Hypothetical dbh is a database handle sth is a s...
    2025-10-25 13:34:02 UTC
  • 6.35. Ruby connection Mysql-MySql2

    We introduced the use of Ruby DBI in the previous chapter. In this chapter, we use Ruby to connect Mysql to more efficient d...
    2025-10-25 13:33:58 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。