ruby中整数支持times,upto,downto,step等几种迭代
irb(main):010:0> 3.times {print "X " }
X X X => 3
irb(main):011:0> 1.upto(5) {|i| print i," "}
1 2 3 4 5 => 1
irb(main):012:0> 99.downto(95) {|i| print i," "}
99 98 97 96 95 => 99
irb(main):013:0> 50.step(80,5) {|i| print i," "}
50 55 60 65 70 75 80 => 50
irb(main):014:0>
irb(main):019:0> 6.times do
irb(main):020:1* puts "#{num.class}: #{num}"
irb(main):021:1> num *=num
irb(main):022:1> end
Fixnum: 81
Fixnum: 6561
Fixnum: 43046721
Bignum: 1853020188851841
Bignum: 3433683820292512484657849089281
Bignum: 11790184577738583171520872861412518665678211592275841109096961
=> 6
irb(main):023:0>
irb(main):006:0> three_times { puts "Hello"}
Hello
Hello
Hello
=> nil
irb(main):007:0> [1,3,5,7,9].find {|v| v*v>30}
=> 7
irb(main):008:0> [1,3,5,7,9].each {|i| puts i}
1
3
5
7
9
=> [1, 3, 5, 7, 9]
irb(main):009:0> [1,3,5,7,9].injuect {|sum,element| sum+element}
NoMethodError: undefined method `injuect' for [1, 3, 5, 7, 9]:Array
from (irb):9
from :0
irb(main):010:0> [1,3,5,7,9].inject {|sum,element| sum+element}
=> 25
irb(main):011:0> [1,3,5,7,9].inject {|sum,element| sum*element}
=> 945
irb(main):012:0>