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:
As the range of a sequence
Scope as a condition
The range used as an interval
6.25.1. As the range of a sequence #
The first and most common use of ranges is to express sequences. A sequence has a starting point, an end point, and a way to generate continuous values in the sequence.
Ruby usage ''..'' and ''...'' the range operator creates these sequences. The two-point form creates a range that contains the specified maximum value, and the three-point form creates a range that does not contain the specified maximum value.
(1..5)#==> 1, 2, 3, 4, 5(1...5)#==> 1, 2, 3, 4('a'..'d')#==> 'a', 'b', 'c', 'd' Sequence 1. 100 is a The output of the above instance is as follows: Scopes implement methods that allow you to traverse them, and you can check their contents in a number of ways: The output of the above instance is as follows: Ranges can also be used as conditional expressions. For example, the following code snippet prints lines from standard input, where the first line of each collection contains words The range can be used in The output of the above instance is as follows: The last use of a range is interval detection: to check whether the specified value is within the specified range. Need to use The output of the above instance is as follows:
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。 Range object that contains two Fixnum a reference to the object. If necessary, you can use the to_a method to convert the scope to a list. Try the following example:Example #
#!/usr/bin/ruby$,=","#Array Value separatorrange1=(1..10).to_arange2=('bar'..'bat').to_aputs"#{range1}"puts"#{range2}"
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10] ["bar", "bas", "bat"]
Example #
#/ Usr/bin/ruby # - * - coding: UTF-8 -*-#Specify a range of digits=0.9putsdigits. include? (5) Ret=digits. inputs "The minimum value is #{ret} "ret=digits. maxputs" The maximum value is #{ret} "ret=digits. subject { | i | i<5 are< conditions do meet not puts" span that the those }> #{ret} "digits. eachdo | digit | puts" in loop # {digit} "end
True The minimum value is 0 Maximum value is 9 Those that do not meet the conditions are [5, 6, 7, 8, 9] In loop 0 In loop 1 In loop 2 In loop 3 In loop 4 In loop 5 In loop 6 In loop 7 In loop 8 In loop 9
6.25.2. Scope as a condition #
start ，the last line contains words end. : whilegetsprintif/start/../end/end
case statement: Example #
#/ Usr/bin/ruby # - * - coding: UTF-8 -*-Score=70result=casescorewhen0.40 "Bad score" when41.. 60 " Almost passing" when61.. 70 "Passing score" when71.. 100 "Good score" else "Wrong score" endputsresult
Passing score
6.25.3. The range used as an interval #
=== equalityoperator to complete the calculation. Example #
#!/usr/bin/ruby#-*- coding: UTF-8 -*-if((1..10)===5)puts"5 in (1..10)"endif(('a'..'j')==='c')puts"c in ('a'..'j')"endif(('a'..'j')==='z')puts"z in ('a'..'j')"end
5 in (1..10) c in ('a'..'j')