I'm trying to sort an array in Ruby by length and alphanumeric:
The desired order would be:
I've been trying array.sort and sort! but none of them seems to do the trick, as they will place the 880 next after 8.
How would I go about doing this the most effective way?
Lets say you have an array:
a = ["site.com?page=7", "site.com?page=8", "site.com?page=9", "site.com?page=880"]
Then you can do:
a = a.sort_by{|t| t.split(/page=/)[1].to_i}
In short I use a custom sort criteria and that criteria is to split the string by "page=", then use the numerical value(to_i) of the string after the first match of page= for the sorting.
You can use the group_by function to group items by length and sort_by to order them alphanumerically within the group, and finally flatten the groups:
list.group_by {|i| i.length}.sort_by{|i| i.first}.collect {|i| i.last.sort}.flatten
A general trick is to zero pad the numbers using a fixed number of decimal places before sorting the array strings.
This can be easily accomplished by the following code:
a = ["site.com?page=9","site.com?page=880""site.com?page=8","site.com?page=7"]
N = 5 # Maximum number of decimal places allowed
a.sort_by { |s| s.gsub(/(\d+)/) { |n| sprintf("%0#{N}d", n.to_i) } }
This works well unless the strings contain any number greater than or equal to 10^N.
