add string representation for runs (#391)

Author: amueller

openml/runs/run.py

@@ -9,7 +9,7 @@
 
 import openml
 from ..tasks import get_task
-from .._api_calls import _perform_api_call, _file_id_to_url, _read_url_files
+from .._api_calls import _perform_api_call, _file_id_to_url
 from ..exceptions import PyOpenMLError
 
 
@@ -54,6 +54,17 @@ def __init__(self, task_id, flow_id, dataset_id, setup_string=None,
         self.tags = tags
         self.predictions_url = predictions_url
 
+    def __str__(self):
+        flow_name = self.flow_name
+        if len(flow_name) > 26:
+            # long enough to show sklearn.pipeline.Pipeline
+            flow_name = flow_name[:26] + "..."
+        return "[run id: {}, task id: {}, flow id: {}, flow name: {}]".format(
+            self.run_id, self.task_id, self.flow_id, flow_name)
+
+    def _repr_pretty_(self, pp, cycle):
+        pp.text(str(self))
+
     def _generate_arff_dict(self):
         """Generates the arff dictionary for uploading predictions to the server.