table_display.py example now uses tableformatter instead of tabulate

Changed the table_display.py example to use the tableformatter module which resuls in nicer looking tables.

Author: tleonhardt

examples/table_display.py

@@ -1,36 +1,78 @@
 #!/usr/bin/env python
 # coding=utf-8
 """A simple example demonstrating the following:
-    1) How to display tabular data within a cmd2 application
+    1) How to display tabular data
     2) How to display output using a pager
 
 NOTE: IF the table does not entirely fit within the screen of your terminal, then it will be displayed using a pager.
 You can use the arrow keys (left, right, up, and down) to scroll around the table as well as the PageUp/PageDown keys.
 You can quit out of the pager by typing "q".  You can also search for text within the pager using "/".
 
-WARNING: This example requires the tabulate module.
+WARNING: This example requires the tableformatter module: https://github.com/python-tableformatter/tableformatter
+- pip install tableformatter
 """
 import functools
 
 import cmd2
-import tabulate
+import tableformatter as tf
 
-# Format to use with tabulate module when displaying tables
-TABLE_FORMAT = 'grid'
+try:
+    from colored import bg
+    BACK_PRI = bg(4)
+    BACK_ALT = bg(2)
+except ImportError:
+    try:
+        from colorama import Back
+        BACK_PRI = Back.LIGHTBLUE_EX
+        BACK_ALT = Back.LIGHTYELLOW_EX
+    except ImportError:
+        BACK_PRI = ''
+        BACK_ALT = ''
+
+# Format to use for the grid style when displaying tables with the tableformatter module
+grid_style = tf.AlternatingRowGrid(BACK_PRI, BACK_ALT) # Use rows of alternating color to assist as a visual guide
 
 # Create a function to format a fixed-width table for pretty-printing using the desired table format
-table = functools.partial(tabulate.tabulate, tablefmt=TABLE_FORMAT)
+table = functools.partial(tf.generate_table, grid_style=grid_style)
+
 
 # Population data from Wikipedia: https://en.wikipedia.org/wiki/List_of_cities_proper_by_population
-EXAMPLE_DATA = [['Shanghai', 'Shanghai', 'China', 'Asia', 24183300, 6340.5, 3814],
-                ['Beijing', 'Hebei', 'China', 'Asia', 20794000, 1749.57, 11885],
-                ['Karachi', 'Sindh', 'Pakistan', 'Asia', 14910352, 615.58, 224221],
-                ['Shenzen', 'Guangdong', 'China', 'Asia', 13723000, 1493.32, 9190],
-                ['Guangzho', 'Guangdong', 'China', 'Asia', 13081000, 1347.81, 9705],
-                ['Mumbai', ' Maharashtra', 'India', 'Asia', 12442373, 465.78, 27223],
-                ['Istanbul', 'Istanbul', 'Turkey', 'Eurasia', 12661000, 620.29, 20411],
+EXAMPLE_DATA = [['Shanghai', 'Shanghai', 'China', 'Asia', 24183300, 6340.5],
+                ['Beijing', 'Hebei', 'China', 'Asia', 20794000, 1749.57],
+                ['Karachi', 'Sindh', 'Pakistan', 'Asia', 14910352, 615.58],
+                ['Shenzen', 'Guangdong', 'China', 'Asia', 13723000, 1493.32],
+                ['Guangzho', 'Guangdong', 'China', 'Asia', 13081000, 1347.81],
+                ['Mumbai', 'Maharashtra', 'India', 'Asia', 12442373, 465.78],
+                ['Istanbul', 'Istanbul', 'Turkey', 'Eurasia', 12661000, 620.29],
                 ]
-EXAMPLE_HEADERS = ['City', 'Province', 'Country', 'Continent', 'Population', 'Area (km^2)', 'Pop. Density (/km^2)']
+
+# Calculate population density
+for row in EXAMPLE_DATA:
+    row.append(row[-2]/row[-1])
+
+
+# TODO: Color row text foreground based on population density
+
+
+def no_dec(num: float) -> str:
+    """Format a floating point number with no decimal places."""
+    return "{}".format(round(num))
+
+
+def two_dec(num: float) -> str:
+    """Format a floating point number with 2 decimal places."""
+    return "{0:.2f}".format(num)
+
+
+# # Column headers plus optional formatting info for each column
+columns = [tf.Column('City', header_halign=tf.ColumnAlignment.AlignCenter),
+           tf.Column('Province', header_halign=tf.ColumnAlignment.AlignCenter),
+           'Country',   # NOTE: If you don't need any special effects, you can just pass a string
+           tf.Column('Continent', cell_halign=tf.ColumnAlignment.AlignCenter),
+           tf.Column('Population', cell_halign=tf.ColumnAlignment.AlignRight, formatter=tf.FormatCommas()),
+           tf.Column('Area (km^2)', cell_halign=tf.ColumnAlignment.AlignRight, formatter=two_dec),
+           tf.Column('Pop. Density (/km^2)', width=12, cell_halign=tf.ColumnAlignment.AlignRight, formatter=no_dec),
+           ]
 
 
 class TableDisplay(cmd2.Cmd):
@@ -51,14 +93,15 @@ def ptable(self, tabular_data, headers=()):
                         - if `headers="keys"`, then dictionary keys or column indices are used
                         - Otherwise, a headerless table is produced
         """
-        formatted_table = table(tabular_data, headers=headers)
-        self.ppaged(formatted_table)
+        formatted_table = table(rows=tabular_data, columns=headers)
+        self.ppaged(formatted_table, chop=True)
 
     def do_table(self, _):
         """Display data on the Earth's most populated cities in a table."""
-        self.ptable(tabular_data=EXAMPLE_DATA, headers=EXAMPLE_HEADERS)
+        self.ptable(EXAMPLE_DATA, columns)
 
 
 if __name__ == '__main__':
     app = TableDisplay()
+    app.debug = True
     app.cmdloop()