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#!/usr/bin/env python
# coding=utf-8
"""A simple example demonstrating the following:
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 tableformatter module: https://github.com/python-tableformatter/tableformatter
- pip install tableformatter
"""
import functools
import cmd2
import tableformatter as tf
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(tf.generate_table, grid_style=grid_style)
# Formatter functions
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)
# Population data from Wikipedia: https://en.wikipedia.org/wiki/List_of_cities_proper_by_population
# ############ Table data formatted as an iterable of iterable fields ############
EXAMPLE_ITERABLE_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],
]
# Calculate population density
for row in EXAMPLE_ITERABLE_DATA:
row.append(row[-2]/row[-1])
# # 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 (km²)', width=7, header_halign=tf.ColumnAlignment.AlignCenter,
cell_halign=tf.ColumnAlignment.AlignRight, formatter=two_dec),
tf.Column('Pop. Density (/km²)', width=12, header_halign=tf.ColumnAlignment.AlignCenter,
cell_halign=tf.ColumnAlignment.AlignRight, formatter=no_dec),
]
# ######## Table data formatted as an iterable of python objects #########
class CityInfo(object):
"""City information container"""
def __init__(self, city: str, province: str, country: str, continent: str, population: int, area: float):
self.city = city
self.province = province
self.country = country
self.continent = continent
self._population = population
self._area = area
def get_population(self):
"""Population of the city"""
return self._population
def get_area(self):
"""Area of city in km²"""
return self._area
def pop_density(data: CityInfo):
"""Calculate the population density from the data entry"""
if isinstance(data, CityInfo):
return no_dec(data.get_population() / data.get_area())
return ''
EXAMPLE_OBJECT_DATA = [CityInfo('Shanghai', 'Shanghai', 'China', 'Asia', 24183300, 6340.5),
CityInfo('Beijing', 'Hebei', 'China', 'Asia', 20794000, 1749.57),
CityInfo('Karachi', 'Sindh', 'Pakistan', 'Asia', 14910352, 615.58),
CityInfo('Shenzen', 'Guangdong', 'China', 'Asia', 13723000, 1493.32),
CityInfo('Guangzho', 'Guangdong', 'China', 'Asia', 13081000, 1347.81),
CityInfo('Mumbai', 'Maharashtra', 'India', 'Asia', 12442373, 465.78),
CityInfo('Istanbul', 'Istanbul', 'Turkey', 'Eurasia', 12661000, 620.29),
]
# If table entries are python objects, all columns must be defined with the object attribute to query for each field
# - attributes can be fields or functions. If a function is provided, the formatter will automatically call
# the function to retrieve the value
obj_cols = [tf.Column('City', attrib='city', header_halign=tf.ColumnAlignment.AlignCenter),
tf.Column('Province', attrib='province', header_halign=tf.ColumnAlignment.AlignCenter),
tf.Column('Country', attrib='country'),
tf.Column('Continent', attrib='continent', cell_halign=tf.ColumnAlignment.AlignCenter),
tf.Column('Population', attrib='get_population', cell_halign=tf.ColumnAlignment.AlignRight,
formatter=tf.FormatCommas()),
tf.Column('Area (km²)', attrib='get_area', width=7, header_halign=tf.ColumnAlignment.AlignCenter,
cell_halign=tf.ColumnAlignment.AlignRight, formatter=two_dec),
tf.Column('Pop. Density (/km²)', width=12, header_halign=tf.ColumnAlignment.AlignCenter,
cell_halign=tf.ColumnAlignment.AlignRight, obj_formatter=pop_density),
]
# TODO: Color row text foreground based on population density
class TableDisplay(cmd2.Cmd):
"""Example cmd2 application showing how you can display tabular data."""
def __init__(self):
super().__init__()
def ptable(self, tabular_data, headers=()):
"""Format tabular data for pretty-printing as a fixed-width table and then display it using a pager.
:param tabular_data: required argument - can be a list-of-lists (or another iterable of iterables), a list of
named tuples, a dictionary of iterables, an iterable of dictionaries, a two-dimensional
NumPy array, NumPy record array, or a Pandas dataframe.
:param headers: (optional) - to print nice column headers, supply this argument:
- headers can be an explicit list of column headers
- if `headers="firstrow"`, then the first row of data is used
- if `headers="keys"`, then dictionary keys or column indices are used
- Otherwise, a headerless table is produced
"""
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(EXAMPLE_ITERABLE_DATA, columns)
def do_object_table(self, _):
"""Display data on the Earth's most populated cities in a table."""
self.ptable(EXAMPLE_OBJECT_DATA, obj_cols)
if __name__ == '__main__':
app = TableDisplay()
app.debug = True
app.cmdloop()
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