Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..
The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5
Any help greatly appreciated..
--
Posted via http://www.ruby-forum.com/.
Hi Raghu
My 2-minute horrible-hack(tm):
input = "abbccdaab"
i = 0;
input.split('').inject({}) {|a,v| a[v] = a[v] ? (a[v] << input[i..-1].index(v)+i) : [input[i..-1].index(v)+i]; i+=1; a}
{"a"=>[0, 6, 7], "b"=>[1, 2, 8], "c"=>[3, 4], "d"=>[5]}
I am sure there has to be a *MUCH* nicer way though, because this is rather ugly...
Cheers,
Peter
___
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On Apr 26, 2008, at 2:55 PM, Raghu Go wrote:
Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5Any help greatly appreciated..
--
Posted via http://www.ruby-forum.com/\.
S2 wrote:
S2 wrote:
irb(main):006:1> ret[c] = ret[c].nil? ? d : d << ret[c]
irb(main):007:1> ret[c].flatten!oh sorry, here are a few things that are not needed:
a = "abbccdaab"
i = 0
ret = Hash.new
a.scan(/./) {|c|
ret[c] = ret[c].nil? ? [i] : ret[c] << i
i = i + 1
}
p a
p ret
The block form of Hash.new gets rid of the if-statement; like this:
str = "abbccdaab"
ar = str.split("")
result = Hash.new{Array.new}
ar.each_with_index do|item,index|
result[item] = result[item]<<index
end
result.each{|k,v| puts k + " = " + v.join(",")}
regards,
Siep
--
Posted via http://www.ruby-forum.com/\.
Hi --
Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5Any help greatly appreciated..
I have this really strong feeling that there's a really easy way, but
I can't think of it or find it. Meanwhile, if you're using 1.9 you
could do something like:
str = "abcdbcdae"
h = Hash.new {|h,k| h[k] = }
str.each_char.map.with_index {|char, i| h[char] << i }
which would put a hash of results in h.
I just have this hunch that there was a way to accumulate offsets from
a scan or gsub operation, but I can't come up with it.
David
On Sat, 26 Apr 2008, Raghu Go wrote:
--
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INTRO TO RAILS June 9-12 Berlin
ADVANCING WITH RAILS June 16-19 Berlin
INTRO TO RAILS June 24-27 London (Skills Matter)
See http://www.rubypal.com for details and updates!
Here is one way.
arr = "abbccdaab".split(//)
arr.uniq.each do |s|
res =
(0...arr.length).each {|x| res << x if arr =~ /#{s}/}
p s, res
end
Harry
On Sat, Apr 26, 2008 at 9:55 PM, Raghu Go <rgowka1@gmail.com> wrote:
Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5Any help greatly appreciated..
--
Posted via http://www.ruby-forum.com/\.
--
A Look into Japanese Ruby List in English
I did a quick test and like Siep's modifications..
Method1 Time elapsed: 0.236999988555908 milliseconds
Siep's modification Method2 Time elapsed: 0.123999834060669 milliseconds
def method1(a)
i = 0
ret = Hash.new
a.scan(/./) {|c|
ret[c] = ret[c].nil? ? [i] : ret[c] << i
i = i + 1
}
p a
p ret
end
def method2(str) #Siep
ar = str.split("")
result = Hash.new{Array.new}
ar.each_with_index do|item,index|
result[item] = result[item]<<index
end
result.each{|k,v| puts k + " = " + v.join(",")}
end
Siep Korteling wrote:
S2 wrote:
S2 wrote:
irb(main):006:1> ret[c] = ret[c].nil? ? d : d << ret[c]
irb(main):007:1> ret[c].flatten!oh sorry, here are a few things that are not needed:
a = "abbccdaab"
i = 0
ret = Hash.new
a.scan(/./) {|c|
ret[c] = ret[c].nil? ? [i] : ret[c] << i
i = i + 1
}
p a
p retThe block form of Hash.new gets rid of the if-statement; like this:
str = "abbccdaab"
ar = str.split("")
result = Hash.new{Array.new}ar.each_with_index do|item,index|
result[item] = result[item]<<index
endresult.each{|k,v| puts k + " = " + v.join(",")}
regards,
Siep
--
Posted via http://www.ruby-forum.com/\.
Hi --
Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5Any help greatly appreciated..
I have this really strong feeling that there's a really easy way, but
I can't think of it or find it. Meanwhile, if you're using 1.9 you
could do something like:str = "abcdbcdae"
h = Hash.new {|h,k| h[k] = }
str.each_char.map.with_index {|char, i| h[char] << i }which would put a hash of results in h.
In 1.8
irb(main):001:0> require 'enumerator'
=> true
irb(main):002:0> str = "abcdbcdae"
=> "abcdbcdae"
irb(main):003:0> ind = Hash.new {|h,k| h[k]=}
=> {}
irb(main):004:0> str.to_enum(:scan,/./).each_with_index {|c,i|ind[c]<<i}
=> #<Enumerable::Enumerator:0x7ff75768>
irb(main):005:0> ind
=> {"a"=>[0, 7], "b"=>[1, 4], "c"=>[2, 5], "d"=>[3, 6], "e"=>[8]}
I just have this hunch that there was a way to accumulate offsets from
a scan or gsub operation, but I can't come up with it.
Like this?
irb(main):017:0> str = "abcdbcdae"
=> "abcdbcdae"
irb(main):018:0> ind = Hash.new {|h,k| h[k]=}
=> {}
irb(main):019:0> str.scan(/./) {|c| ind[c] << $`.length}
=> "abcdbcdae"
irb(main):020:0> ind
=> {"a"=>[0, 7], "b"=>[1, 4], "c"=>[2, 5], "d"=>[3, 6], "e"=>[8]}
Cheers
robert
On 26.04.2008 16:53, David A. Black wrote:
On Sat, 26 Apr 2008, Raghu Go wrote:
> Hi - I am trying to figure out the ruby way of printing all occurances
> of a character in a string..
>
> The index method on string gives only the first occurance only.
I thought of the 'indexes' method, but that works in reverse. So I
made my own version:
class Array
def all_indexes val
(0..length).map{|i|self[i]==val ? i : nil}.compact
end
alias :all_indicies :all_indexes
end
p 'hello world'.split('').all_indicies('l')
=> [2, 3, 9]
>
> Example input string - abbccdaab
> desired output - 'a' = 0 6 7
> 'b' = 1 2 8
> 'c' = 3 4
> 'd' = 5
>
> Any help greatly appreciated..
Source = 'abbccdaab'
s=Source.split('')
s.uniq.each{|v| puts "'#{v}' = #{s.all_indexes(v)*' '}"}
=> 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5
-Adam
On Sat, Apr 26, 2008 at 9:55 PM, Raghu Go <rgowka1@gmail.com> wrote:
Hi --
On Sun, 27 Apr 2008, Robert Klemme wrote:
On 26.04.2008 16:53, David A. Black wrote:
Hi --
On Sat, 26 Apr 2008, Raghu Go wrote:
Hi - I am trying to figure out the ruby way of printing all occurances
of a character in a string..The index method on string gives only the first occurance only.
Example input string - abbccdaab
desired output - 'a' = 0 6 7
'b' = 1 2 8
'c' = 3 4
'd' = 5Any help greatly appreciated..
I have this really strong feeling that there's a really easy way, but
I can't think of it or find it. Meanwhile, if you're using 1.9 you
could do something like:str = "abcdbcdae"
h = Hash.new {|h,k| h[k] = }
str.each_char.map.with_index {|char, i| h[char] << i }which would put a hash of results in h.
In 1.8
irb(main):001:0> require 'enumerator'
=> true
irb(main):002:0> str = "abcdbcdae"
=> "abcdbcdae"
irb(main):003:0> ind = Hash.new {|h,k| h[k]=}
=> {}
irb(main):004:0> str.to_enum(:scan,/./).each_with_index {|c,i|ind[c]<<i}
=> #<Enumerable::Enumerator:0x7ff75768>
irb(main):005:0> ind
=> {"a"=>[0, 7], "b"=>[1, 4], "c"=>[2, 5], "d"=>[3, 6], "e"=>[8]}I just have this hunch that there was a way to accumulate offsets from
a scan or gsub operation, but I can't come up with it.Like this?
irb(main):017:0> str = "abcdbcdae"
=> "abcdbcdae"
irb(main):018:0> ind = Hash.new {|h,k| h[k]=}
=> {}
irb(main):019:0> str.scan(/./) {|c| ind[c] << $`.length}
=> "abcdbcdae"
irb(main):020:0> ind
=> {"a"=>[0, 7], "b"=>[1, 4], "c"=>[2, 5], "d"=>[3, 6], "e"=>[8]}
It may well have been that, or something like it.
David
--
Rails training from David A. Black and Ruby Power and Light:
INTRO TO RAILS June 9-12 Berlin
ADVANCING WITH RAILS June 16-19 Berlin
INTRO TO RAILS June 24-27 London (Skills Matter)
See http://www.rubypal.com for details and updates!
I apologise for the complete ugliness of this code 
Look away of you're screamish!
ARGV.to_s.split(/\s*/).map{|x|x.downcase}.inject(Hash.new(0)){|h,x|h[x]
+=1 and h}.each{|i,h| print "#{i}(#{h}), "}
Foobar, output:
a(1), b(1), o(2), f(1), r(1)
Whoops, I didn't read the question properly, this prints all
occurances, not positions..