CODEWITHSUNDEEP
arraysrubystringsortinginteger
vikas95prasad
vikas95prasad

Reputation: 1332

Efficient way to sort an array of numbers and string in ruby?

Input : 

arr = [4,2,'b',5,'c','a',7]

Output:

[2,4,5,7,'a','b','c']

I can think of this : 

int_arr = arr.select {|x| x.instance_of?(Integer)}.sort
str_arr = arr.select {|x| x.instance_of?(String)}.sort

int_arr + str_arr

Please suggest a efficient way to do it.

Upvotes: 6

Views: 853

Answers (2)

Cary Swoveland
Cary Swoveland

Reputation: 110685

arr.sort_by { |e| [e.is_a?(Integer) ? 0 : 1, e] }
  #=> [2, 4, 5, 7, "a", "b", "c"] 

[22, 'efg', 0, 'abc', -4].sort_by { |e| [e.is_a?(Integer) ? 0 : 1, e] }
  #=> [-4, 0, 22, "abc", "efg"]

See Enumerable#sort_by. sort_by performs pair-wise comparisons of 2-element arrays using the method Array#<=>. See especially the third paragraph of that doc.

The following could be used if, as in the example, the integers are single digits and the strings are single characters.

arr.sort_by(&:ord)
  #=> [2, 4, 5, 7, "a", "b", "c"]

See Integer#ord and String#ord.

Upvotes: 3

Sebasti&#225;n Palma
Sebasti&#225;n Palma

Reputation: 33430

One way is to partition your array by those elements being Integer, to make sure they remain first and then sort the elements of each array:

[4,2,'b',5,'c','a',7].partition { |e| e.is_a?(Integer) }.flat_map(&:sort)
# [2, 4, 5, 7, "a", "b", "c"]

Upvotes: 7

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