fix #37 - split

pykusto/expressions.py

@@ -238,8 +238,8 @@ class StringExpression(BaseExpression):
 
     def split(self, delimiter: StringType, requested_index: NumberType = None) -> 'ArrayExpression':
         if requested_index is None:
-            return ArrayExpression(KQL('split({}, {}'.format(self.kql, delimiter)))
-        return ArrayExpression(KQL('split({}, {}, {}'.format(self.kql, delimiter, requested_index)))
+            return ArrayExpression(KQL('split({}, "{}")'.format(_subexpr_to_kql(self.kql), delimiter)))
+        return ArrayExpression(KQL('split({}, "{}", {})'.format(_subexpr_to_kql(self.kql), delimiter, requested_index)))
 
     def equals(self, other: StringType, case_sensitive: bool = False) -> BooleanExpression:
         return BooleanExpression.binary_op(self, ' == ' if case_sensitive else ' =~ ', other)

pykusto/functions.py

@@ -548,7 +548,8 @@ def sign(expr: NumberType) -> NumberExpression:
 # def sin(self): return
 #
 #
-# def split(self): return
+def split(string: StringType, delimiter: StringType, requested_index: NumberType = None) -> 'ArrayExpression':
+    return StringExpression(KQL(string)).split(delimiter, requested_index)
 
 
 def sqrt(expr: NumberType) -> NumberExpression:

test/test_functions.py

@@ -389,6 +389,20 @@ class TestFunction(TestBase):
             Query().where(f.substring(col.foo, col.bar, 4) == 'ABC,ABC').render()
         )
 
+    def test_split(self):
+        self.assertEqual(
+            ' | extend foo = (split(bar, "_", 3))',
+            Query().extend(foo=f.split(col.bar, "_", 3)).render()
+        )
+        self.assertEqual(
+            ' | extend foo = (split(bar, "_")[3])',
+            Query().extend(foo=f.split(col.bar, "_")[3]).render()
+        )
+        self.assertEqual(
+            ' | extend foo = (split("1_2", "_")[3])',
+            Query().extend(foo=f.split("1_2", "_")[3]).render()
+        )
+
     def test_tobool(self):
         self.assertEqual(
             " | where tobool(foo)",