Programming Ruby String

Ruby

String literal
"string"
'string'

?\u20AC==?€

  1. concatenate string

< and >=

s='hello'
puts s[0] #output 'h'
puts s[s.length-1] #output 'o'
puts s[-2] #output 'l'
puts s[-s.length] #output 'h'
puts s[s.length] #nil :there is no character at that index character

s[0]=?H
puts s[0] #output:Replace first character with a capital H
s[-1]=?O
puts s[-1] #output:Replace first character with o capital O
puts s #output 'HellO'
s[s.length]=?! beyond the end of the string
puts s #output 'Hello!'


#substring
s="hello"
puts s[0,2] #"he"
puts s[-1,1] #"o"
puts s[0,0] #""
puts s[0,10] #"hello" : returns all the characters that are available
puts s[s.length,1] #""
puts s[s.length+1,1] #""
puts [0,-1] #-1

puts s[2..3] #"ll"
puts s[-3..-1] #"llo"
puts s[0..0] #"h"
puts"\n"

puts s[0...0] #"":this Range is empty
puts s[2..1] #"":this Range is also empty
puts s[7..10] #nil:this Range is outside the string
puts s[-2..-1]="p!" #replacement:s becomes "help!"
puts s[0...0]="Please " #Insertion:s becomes "please help!"
puts s
s[6..10]="" #Deletion:s becomes "please!"


s="hello"
while(s["l"])
s["l"]="L"
end
puts s #replase "l" to "L"

s[/[aeiou]/]='*'
puts s #replase first vowel with an asterisk