Ruby Array Sort By Date Desc

Meaning that you first sort by date for example but because you have multiple things with the same date then you have a tie.

Ruby array sort by date desc.

First adding reverse or descending option to sort by. Just to clarify i m not sure what you mean by adding secondary key sort order key word being secondary. User system total real sort 1 340000 0 010000 1 350000 1 346331 sort reverse 1 300000 0 000000 1 300000 1 310446 sort by a bar 0 430000 0 000000 0 430000 0 429606 sort by a bar 1 0 420000 0 000000 0 420000 0 414383 sort by reverse. Being a high level language you won t be implementing sorting algorithms in ruby if you care about performance and besides sorting arrays and other collections are yet more things ruby does.

Ruby program that uses descending sort order contains six different numbers. User system total real sort 1 340000 0 010000 1 350000 1 346331 sort reverse 1 300000 0 000000 1 300000 1 310446 sort by a bar 0 430000 0 000000 0 430000 0 429606 sort by a bar 1 0 420000 0 000000 0 420000 0 414383 sort by reverse. Please note that these results are different in ruby 1 9. Returns a new array.

The second form creates a copy of the array passed as a parameter the array is generated by calling to ary on the parameter. User system total real sort 0 180000 0 000000 0 180000 0 175469 sort by 1 980000 0 040000 2 020000 2 013586 however consider the case where comparing the keys is a non trivial operation. Sorting was a preoccupation for computer scientists from early on. The following code sorts some files on modification time using the basic sort method.

I think it may be useful for some cases but it s only slightly better than sort by reverse. You don t need to write any fancy algorithms to get the result you want. Here are results for ruby 1 9 3p194 2012 04 20 revision 35410 x86 64 darwin10 8 0. Array sortby function o return new date o date.

Please note that these results are different in ruby 1 9. If your date is not directly comparable make a comparable date out of it e g. There were many algorithms that came into and fell out of use and still today new algorithms are pushing the boundaries of performance. You can also use this to sort by multiple criteria if you return an array of values.

Array sortby function o return o date. Understanding ruby s built in sorting methods. Sort with blocks sort in descending order and sort in place. When a size and an optional default are sent an array is created with size copies of default take notice that all elements will reference the same object default.

Sort by handles multiple parameters by sorting the collection according to the first parameter. Sorting an array in ruby is easy. Now we have tasks sorted first by due date and then by priority. Numbers 1 200 900 300 1000 5 sort from highest to lowest descending.

In the first form if no arguments are sent the new array will be empty. Second adding secondary key sort order to sort by.