[hotfix][python][examples] Add a few examples about the basic operati…

…ons of Python Table API & DataStream API

flink-python/pyflink/examples/datastream/basic_operations.py

@@ -0,0 +1,76 @@
+################################################################################
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+# limitations under the License.
+################################################################################
+import json
+import logging
+import sys
+
+from pyflink.common import Types
+from pyflink.datastream import StreamExecutionEnvironment
+
+
+def show(ds, env):
+    ds.print()
+    env.execute()
+
+
+def basic_operations():
+    env = StreamExecutionEnvironment.get_execution_environment()
+    env.set_parallelism(1)
+
+    # define the source
+    ds = env.from_collection(
+        collection=[
+            (1, '{"name": "Flink", "tel": 123, "addr": {"country": "Germany", "city": "Berlin"}}'),
+            (2, '{"name": "hello", "tel": 135, "addr": {"country": "China", "city": "Shanghai"}}'),
+            (3, '{"name": "world", "tel": 124, "addr": {"country": "USA", "city": "NewYork"}}'),
+            (4, '{"name": "PyFlink", "tel": 32, "addr": {"country": "China", "city": "Hangzhou"}}')
+        ],
+        type_info=Types.ROW_NAMED(["id", "info"], [Types.INT(), Types.STRING()])
+    )
+
+    # map
+    def update_tel(data):
+        # parse the json
+        json_data = json.loads(data.info)
+        json_data['tel'] += 1
+        return data.id, json.dumps(json_data)
+
+    show(ds.map(update_tel), env)
+    # (1, '{"name": "Flink", "tel": 124, "addr": {"country": "Germany", "city": "Berlin"}}')
+    # (2, '{"name": "hello", "tel": 136, "addr": {"country": "China", "city": "Shanghai"}}')
+    # (3, '{"name": "world", "tel": 125, "addr": {"country": "USA", "city": "NewYork"}}')
+    # (4, '{"name": "PyFlink", "tel": 33, "addr": {"country": "China", "city": "Hangzhou"}}')
+
+    # filter
+    show(ds.filter(lambda data: data.id == 1).map(update_tel), env)
+    # (1, '{"name": "Flink", "tel": 124, "addr": {"country": "Germany", "city": "Berlin"}}')
+
+    # key by
+    show(ds.map(lambda data: (json.loads(data.info)['addr']['country'],
+                              json.loads(data.info)['tel']))
+           .key_by(lambda data: data[0]).sum(1), env)
+    # ('Germany', 123)
+    # ('China', 135)
+    # ('USA', 124)
+    # ('China', 167)
+
+
+if __name__ == '__main__':
+    logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(message)s")
+
+    basic_operations()