added timestamp import to matplotlib linecharts (#396) (#397)

* added timestamp import

* fix broken test

* version lock to pandas version < 1.3

.github/workflows/python-app.yml

@@ -46,13 +46,13 @@ jobs:
         pip install -r requirements-dev.txt
         pip install sqlalchemy
 
-        pip uninstall -y  lux-widget
-        pip install git+git://github.com/lux-org/lux-widget.git
-        # Temporary Fix (#372)
-        cd /opt/hostedtoolcache/Python/3.7.10/x64/lib/python3.7/site-packages/luxwidget/
-        mkdir labextension
-        cd labextension
-        wget https://raw.githubusercontent.com/lux-org/lux-widget/master/luxwidget/nbextension/package.json
+        # pip uninstall -y  lux-widget
+        # pip install git+git://github.com/lux-org/lux-widget.git
+        # # Temporary Fix (#372)
+        # cd /opt/hostedtoolcache/Python/3.7.10/x64/lib/python3.7/site-packages/luxwidget/
+        # mkdir labextension
+        # cd labextension
+        # wget https://raw.githubusercontent.com/lux-org/lux-widget/master/luxwidget/nbextension/package.json
 
     - name: Upload data to Postgres
       run: |

lux/vislib/matplotlib/LineChart.py

@@ -110,6 +110,7 @@ def initialize_chart(self):
 
         self.code += "import numpy as np\n"
         self.code += "from math import nan\n"
+        self.code += "from pandas import Timestamp\n"
         self.code += f"df = pd.DataFrame({str(self.data.to_dict())})\n"
         self.code += f"fig, ax = plt.subplots()\n"
         self.code += f"x_pts = df['{x_attr.attribute}']\n"

requirements.txt

@@ -1,8 +1,8 @@
 scipy>=1.3.3
 altair>=4.0.0
 numpy>=1.16.5
-pandas>=1.2.0
+pandas>=1.2.0,<1.3.0
 scikit-learn>=0.22
 matplotlib>=3.0.0
 lux-widget>=0.1.4
-iso3166
+iso3166