Replaced isnan Jinja filter with more versatile isnull filter (#138)

* Make isnan jinja filter more potent by switching to pandas function (now also works on timedelta objects, for example)

* Rename jinja filter

Co-authored-by: F.N. Claessen <felix@seita.nl>

flexmeasures/ui/__init__.py

@@ -4,7 +4,7 @@
 from flask.blueprints import BlueprintSetupState
 from flask import send_from_directory
 from flask_security import login_required, roles_accepted
-import numpy as np
+import pandas as pd
 import rq_dashboard
 from humanize import naturaldelta
 
@@ -124,7 +124,7 @@ def add_jinja_filters(app):
     app.jinja_env.filters["naturalized_timedelta"] = naturaldelta
     app.jinja_env.filters["capitalize"] = capitalize
     app.jinja_env.filters["parameterize"] = parameterize
-    app.jinja_env.filters["isnan"] = np.isnan
+    app.jinja_env.filters["isnull"] = pd.isnull
     app.jinja_env.filters["hide_nan_if_desired"] = (
         lambda x: ""
         if x in ("nan", "nan%", "NAN")

flexmeasures/ui/templates/views/portfolio.html

@@ -147,7 +147,7 @@ <h3>Market status</h3>
                         <td>{{ market.display_name }}</td>
                         <td>{{ market.unit[:3] }}</td>
                         <td>
-                            {% if not average_prices[market.name] | isnan %}
+                            {% if not average_prices[market.name] | isnull %}
                             {{ "{:,.2f}".format( average_prices[market.name] ) }} {{ market.unit }}
                             {% else %}
                             Unknown for the requested period