Understanding ruby s built in sorting methods.
Ruby array sort by date desc.
Now we have tasks sorted first by due date and then by priority.
Sort with blocks sort in descending order and sort in place.
If your date is not directly comparable make a comparable date out of it e g.
Sorting was a preoccupation for computer scientists from early on.
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.
Numbers 1 200 900 300 1000 5 sort from highest to lowest descending.
There were many algorithms that came into and fell out of use and still today new algorithms are pushing the boundaries of performance.
The second form creates a copy of the array passed as a parameter the array is generated by calling to ary on the parameter.
Meaning that you first sort by date for example but because you have multiple things with the same date then you have a tie.
Second adding secondary key sort order to sort by.
Please note that these results are different in ruby 1 9.
If there are any ties in this case multiple tasks due on monday 5 4 it will fall back to the next parameter given in our case priority.
First adding reverse or descending option to sort by.
Ruby sort arrays use the sort method.
I think it may be useful for some cases but it s only slightly better than sort by reverse.
Just to clarify i m not sure what you mean by adding secondary key sort order key word being secondary.
Sorting an array in ruby is easy.
Array sortby function o return new date o date.
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.
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.
Ruby program that uses descending sort order contains six different numbers.
You can also use this to sort by multiple criteria if you return an array of values.
The following code sorts some files on modification time using the basic sort method.
Here are results for ruby 1 9 3p194 2012 04 20 revision 35410 x86 64 darwin10 8 0.
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.
You don t need to write any fancy algorithms to get the result you want.
Array sortby function o return o date.
Here are results for ruby 1 9 3p194 2012 04 20 revision 35410 x86 64 darwin10 8 0.
In the first form if no arguments are sent the new array will be empty.