distinct

distinct(X)

Return the distinct elements from X. Since version 3.00.4, the order of the returned elements matches the order of their first appearance in the input.

X is a vector or array vector.

distinct(4 5 5 2 3)
// output: [4,5,2,3]

a = array(INT[], 0, 10).append!([1 2 3,  4 5, 6 7 8, 9 10])
distinct(a)
// output: [1,2,3,4,5,6,7,8,9,10]

t=table(3 1 2 2 3 as x);
select distinct x from t;

select sort(distinct(x)) as x from t;

The function distinct returns a vector, while the function set returns a set.

x=set(4 5 5 2 3)
x
// output: set(3,2,5,4)

x.intersection(set(2 5))
// output: set(2,5)

For in-memory or distributed tables, distinct can be used with group by to return an array vector of unique values for each group.

dbName = "dfs://testdb"
if(existsDatabase(dbName)){
   dropDatabase(dbName)
}

db=database("dfs://testdb", VALUE, 2012.01.11..2012.01.29)

n=100
t=table(take(2012.01.11..2012.01.29, n) as date, symbol(take("A"+string(21..60), n)) as sym, take(100, n) as val)

pt=db.createPartitionedTable(t, `pt, `date).append!(t)
result=select distinct(date) from pt group by sym
select sym, distinct_date from result where sym=`A21