Standard Types(Chapter 6 of Programming Ruby)

1 3.times { print "X " }
2 1.upto(5) {|i| print i, " " }
3 99.downto(95) {|i| print i, " " }
4 50.step(80, 5) {|i| print i, " " }
5 
6 produces:
7 X X X 1 2 3 4 5 99 98 97 96 95 50 55 60 65 70 75 80

 

　　In Ruby, these sequences are created using the . . and . . . range operators. The two-dot form creates an inclusive range, and the three-dot form creates a range that excludes the specified high value.

 

　　A final use of the versatile range is as an interval test: seeing whether some value falls within the interval represented by the range.

1 (1..10) === 5 # => true
2 (1..10) === 15 # => false
3 (1..10) === 3.14159 # => true
4 ('a'..'j') === 'c' # => true
5 ('a'..'j') === 'z' # => false

 

 

 

转载于:https://www.cnblogs.com/zhtf2014/archive/2010/06/28/1766648.html