Re: sort elements

On Mar 23, 2010, at 03:35 , Juan Gf wrote:

> Ryan Davis wrote:
>> On Mar 23, 2010, at 02:47 , Juan Gf wrote:
>>=20
>>> 2  car
>>> 1  apple
>>> 1  tree
>>>=20
>>> Any ideas?
>>=20
>> Read aloud what the code says, translated to natural language =
(English=20
>> or otherwise, doesn't matter... just raise it to human thought =
level).=20

> a =3D 'Apple car caR house tree ice ice ice house'
> b =3D a.downcase.split(' ')
> b.uniq.each do |element|
> puts "#{b.count(element)}\t#{element}"
> end

> CONVERT THE TEXT IN LOWER-CASE AND THEN SPLIT THE TEXT INTO SINGLE=20
> [a list of] WORDS! THEN COUNT [and print] HOW MANY TIMES EVERY SINGLE =
WORD APPEARS!

I'd say that is mostly correct. You're glossing over the uniq part:

Then walk over each unique word and print how many times it occurs in =
the list of words.

>> Then say aloud what you want it to do, step by step.=20
>=20
> CONVERT THE TEXT IN LOWER-CASE AND THEN SPLIT THE TEXT INTO [a list =
of] SINGLE WORDS! THEN COUNT HOW MANY TIMES EVERY SINGLE WORD APPEARS! =
THEN SORT=20
> [the list] THE RESULTS: FIRST THE MORE COMMON WORDS AND AFTER THE LESS =
COMMON WORDS

better.

>> What's the difference?=20
>=20
> the difference is "THEN SORT THE RESULTS: FIRST THE MORE COMMON WORDS=20=

> AND AFTER THE LESS COMMON WORDS FINALLY BLOODY COMPUTER BRING ME A=20
> PIZZA!"
>=20
>> Translate that difference back down to code.
>=20
> I tried to use .sort like this:
>=20
> "b.uniq.each do |element|
>  puts "#{(b.count(element)).sort}\t#{element}"
> end"
>=20
> but obviously it doesn't work.

see how I modified your description to "THEN SORT [the list]"? That's =
what you're missing. You're not paying attention to what your each is =
iterating over. As others have pointed out, there are a lot of ways to =
do this, my favorite is to change the description to:

Convert the text to lower-case and split into a list of words. Create a =
hash to count the words (default to 0). Enumerate the list of words and =
increment the hash by one for every word seen. Enumerate the hash sorted =
by the word counts (descending) and name (ascending) and print the word =
and occurances.


input =3D 'Apple car caR house tree ice ice ice house'
count =3D Hash.new 0
input.downcase.split(' ').each do |word|
  count[word] +=3D 1
end
count.sort_by { |word, count| [-count, word] }.each do |word, count|
  puts "%4d: %s" % [count, word]
end

which outputs:

   3: ice
   2: car
   2: house
   1: apple
   1: tree