public void TestUDF()
{
// Single UDF.
Func <Column, Column, Column> udf1 = Udf <int?, string, string>(
(age, name) => name + " is " + (age ?? 0));
{
Row[] rows = _df.Select(udf1(_df["age"], _df["name"])).Collect().ToArray();
Assert.Equal(3, rows.Length);
Assert.Equal("Michael is 0", rows[0].GetAs <string>(0));
Assert.Equal("Andy is 30", rows[1].GetAs <string>(0));
Assert.Equal("Justin is 19", rows[2].GetAs <string>(0));
}
// Chained UDFs.
Func <Column, Column> udf2 = Udf <string, string>(str => $"hello {str}!");
{
Row[] rows = _df
.Select(udf2(udf1(_df["age"], _df["name"])))
.Collect()
.ToArray();
Assert.Equal(3, rows.Length);
Assert.Equal("hello Michael is 0!", rows[0].GetAs <string>(0));
Assert.Equal("hello Andy is 30!", rows[1].GetAs <string>(0));
Assert.Equal("hello Justin is 19!", rows[2].GetAs <string>(0));
}
// Multiple UDFs:
{
Row[] rows = _df
.Select(udf1(_df["age"], _df["name"]), udf2(_df["name"]))
.Collect()
.ToArray();
Assert.Equal(3, rows.Length);
Assert.Equal("Michael is 0", rows[0].GetAs <string>(0));
Assert.Equal("hello Michael!", rows[0].GetAs <string>(1));
Assert.Equal("Andy is 30", rows[1].GetAs <string>(0));
Assert.Equal("hello Andy!", rows[1].GetAs <string>(1));
Assert.Equal("Justin is 19", rows[2].GetAs <string>(0));
Assert.Equal("hello Justin!", rows[2].GetAs <string>(1));
}
}