Ruby编程之字符串赋值和字符串索引

s = "hello world"
print( "1) s='#{s}' and s.object_id=#{s.object_id}\n" )
s = s + "!" # this creates a new string object
print( "2) s='#{s}' and s.object_id=#{s.object_id}\n" )
s = s.capitalize # this creates a new string object
print( "3) s='#{s}' and s.object_id=#{s.object_id}\n" )
s.capitalize! # but this modifies the original string object
print( "4) s='#{s}' and s.object_id=#{s.object_id}\n" )
s[1] = 'A' # this also modifies the original string object
print( "5) s='#{s}' and s.object_id=#{s.object_id}\n" )

1) s='hello world' and s.object_id=60
2) s='hello world!' and s.object_id=80
3) s='Hello world!' and s.object_id=100
4) s='Hello world!' and s.object_id=100
5) s='HAllo world!' and s.object_id=100

s = "Hello world"
puts( s[1] ) #=> Ruby 1.8 displays 101; Ruby 1.9 displays 'e'
s = "Hello world"
puts( s[1,1] ) # prints out 'e'

e
e

puts( s[1].ord)

101

s = "Hello world"
puts( s[1] )
achar=s[1]
puts( achar )
puts( s[1,1] )
puts( achar.ord )

e
e
e
101

puts( s[1,3] )

ell

puts( s[1..3] ) # also prints 'ell'
puts( s[-1,1] ) # prints 'd'
puts( s[-5,5] ) # prints 'world'
puts( s[-5..5] ) # this prints an empty string!
puts( s[-5..-1] ) # prints 'world'
puts(s.length) #=> 11
puts(s.reverse!) #=> Hello world
puts(s.reverse) #=> dlrow olleH
puts(s.upcase)#=> HELLO WORLD
puts(s.capitalize) #=> Hello world
puts(s.swapcase) #=> hELLO WORLD
puts(s.downcase) #=> hello world
puts(s.insert(7,"NOT ")) #=> hello wNOT orld
puts(s.squeeze)#=> helo wNOT orld
puts(s.split) #=> ["helo", "wNOT", "orld"]

ell
d
world

world
11
dlrow olleH
Hello world
DLROW OLLEH
Dlrow olleh
DLROW OLLEh
dlrow olleh
dlrow oNOT lleH
dlrow oNOT leH
dlrow
oNOT
lleH

开发环境:Rubymine

The book of Ruby----A hands-on guide for the Adventurous---[美]Huw Collingbourne---no starch press