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