You need to construct your function sortGT, so that it compares pairs the way you want it: sortGT (a1, b1) (a2, b2) | a1 < a2 = GT | a1 > a2 = LT | a1 == a2 = compare b1 b2 Using this you get the following results (I used ghci): *Main Data.List> sortBy … Read more
Heap sort unstable example Consider array 21 20a 20b 12 11 8 7 (already in max-heap format) here 20a = 20b just to differentiate the order we represent them as 20a and 20b While heapsort first 21 is removed and placed in the last index then 20a is removed and placed in last but one … Read more
Do your groupby, and use reset_index() to make it back into a DataFrame. Then sort. grouped = df.groupby(‘mygroups’).sum().reset_index() grouped.sort_values(‘mygroups’, ascending=False)
You are sorting an array of strings using StringVector. To minimize overhead, you could sort an array of strings. package main import ( “fmt” “sort” ) func main() { m := map[string]string{“b”: “15”, “z”: “123123”, “x”: “sdf”, “a”: “12”} mk := make([]string, len(m)) i := 0 for k, _ := range m { mk[i] = … Read more
What is your question, precisely? Are you asking whether NaN exists, or whether it can be obtained as the result of accidental or voluntary computations? Yes, it does and it can. The sort of data structure that requires a total order for keys breaks down completely when the provided order is not a total order. … Read more
SELECT foo, count(bar) FROM mytable GROUP BY bar ORDER BY count(bar) DESC; The group by statement tells aggregate functions to group the result set by a column. In this case “group by bar” says count the number of fields in the bar column, grouped by the different “types” of bar. A better explanation is here: … Read more
There are at least three ways to do it. Flipped comparison function vec.sort_by(|a, b| b.cmp(a)) This switches around the order in which elements are compared, so that smaller elements appear larger to the sorting function and vice versa. Wrapper with reverse Ord instance use std::cmp::Reverse; vec.sort_by_key(|w| Reverse(*w)); Reverse is a generic wrapper which has an … Read more
Use the sort.Slice (available since Go 1.8) or the sort.Sort function to sort a slice of values. With both functions, the application provides a function that tests if one slice element is less than another slice element. To sort by last name and then first name, compare last name and then first name: // If … Read more
Natural ordering is a kind of alphanumerical sort which seems natural to humans. In a classical alphanumerical sort we will have something like : 1 10 11 12 2 20 21 3 4 5 6 7 If you’re using Natural ordering, it will be : 1 2 3 4 5 6 7 10 11 12 … Read more
Two arguments come to my mind: Quicksort/Introsort is more flexible: Quicksort and Introsort work well with all kinds of data. All you need for sorting is the possibility to compare items. This is trivial with numbers but you can sort other data as well. Radix sort on the other hand just sorts things by their … Read more