exists

exists(path)

path is a STRING scalar/vector, indicating the path of file(s) or folder(s).

Check if the specified file(s) or folder(s) exist. It can be used in the distributed files system to check if the specified folder(s) exist.

t=table(1..10 as ID, rand(1.0, 10) as x);
saveText(t, "C:/DolphinDB/Data/t.txt");

exists("C:/DolphinDB/Data/t.txt");
// output
true
exists("C:/DolphinDB/Data/t1.txt");
// output
false
exists("C:/DolphinDB/Data");
// output
true

exists(["C:/DolphinDB/Data/t.txt","C:/DolphinDB/Data/t1.txt","C:/DolphinDB/Data"]);
// output
[true,false,true]

To check if a folder (or folders) exists in the distributed files system (the following script must be executed at a data node in a cluster):

n=1000
ID=rand(10, n)
dates=2017.08.07..2017.08.11
date=rand(dates, n)
x=rand(10.0, n)
t=table(ID, date, x)

db = database("dfs://valueDB", VALUE, 2017.08.07..2017.08.11)
pt = db.createPartitionedTable(t, `pt, `date);
pt.append!(t);

exists("dfs://valueDB/20170807");
// output
true