Update readability country.py

country.py

@@ -1,87 +1,111 @@
-from tkinter import *
+# country.py
+
+import tkinter
 from tkinter import ttk
-root = Tk()
-
-# Initialize our country "databases":
-#  - the list of country codes (a subset anyway)
-#  - parallel list of country names, same order as the country codes
-#  - a hash table mapping country code to population
-countrycodes = ('ar', 'au', 'be', 'br', 'ca', 'cn', 'dk', 'fi', 'fr', 'gr', 'in', 'it', 'jp', 'mx', 'nl', 'no', 'es', 'se', 'ch')
-countrynames = ('Argentina', 'Australia', 'Belgium', 'Brazil', 'Canada', 'China', 'Denmark', \
-        'Finland', 'France', 'Greece', 'India', 'Italy', 'Japan', 'Mexico', 'Netherlands', 'Norway', 'Spain', \
-        'Sweden', 'Switzerland')
-cnames = StringVar(value=countrynames)
-populations = {'ar':41000000, 'au':21179211, 'be':10584534, 'br':185971537, \
-        'ca':33148682, 'cn':1323128240, 'dk':5457415, 'fi':5302000, 'fr':64102140, 'gr':11147000, \
-        'in':1131043000, 'it':59206382, 'jp':127718000, 'mx':106535000, 'nl':16402414, \
-        'no':4738085, 'es':45116894, 'se':9174082, 'ch':7508700}
+
+root = tkinter.Tk()
+
+"""
+Initialize our country "databases":
+ - the list of country codes (a subset anyway);
+ - parallel list of country names, same order as the country codes;
+ - a hash table mapping country code to population.
+"""
+countrycodes = ('ar', 'au', 'be', 'br', 'ca', 'cn', 'dk', 'fi', 'fr', 'gr',
+                'in', 'it', 'jp', 'mx', 'nl', 'no', 'es', 'se', 'ch')
+countrynames = ('Argentina', 'Australia', 'Belgium', 'Brazil', 'Canada',
+                'China', 'Denmark', 'Finland', 'France', 'Greece', 'India',
+                'Italy', 'Japan', 'Mexico', 'Netherlands', 'Norway', 'Spain',
+                'Sweden', 'Switzerland')
+cnames = tkinter.StringVar(value=countrynames)
+populations = {'ar': 41000000, 'au': 21179211, 'be': 10584534,
+               'br': 185971537, 'ca': 33148682, 'cn': 1323128240,
+               'dk': 5457415, 'fi': 5302000, 'fr': 64102140, 'gr': 11147000,
+               'in': 1131043000, 'it': 59206382, 'jp': 127718000,
+               'mx': 106535000, 'nl': 16402414, 'no': 4738085, 'es': 45116894,
+               'se': 9174082, 'ch': 7508700}
 
 # Names of the gifts we can send
-gifts = { 'card':'Greeting card', 'flowers':'Flowers', 'nastygram':'Nastygram'}
+gifts = {'card': 'Greeting card',
+         'flowers': 'Flowers',
+         'nastygram': 'Nastygram'}
 
 # State variables
-gift = StringVar()
-sentmsg = StringVar()
-statusmsg = StringVar()
-
-# Called when the selection in the listbox changes; figure out
-# which country is currently selected, and then lookup its country
-# code, and from that, its population.  Update the status message
-# with the new population.  As well, clear the message about the
-# gift being sent, so it doesn't stick around after we start doing
-# other things.
+gift = tkinter.StringVar()
+sentmsg = tkinter.StringVar()
+statusmsg = tkinter.StringVar()
+
+"""
+Called when the selection in the listbox changes; figure out
+which country is currently selected, and then lookup its country
+code, and from that, its population.  Update the status message
+with the new population.  As well, clear the message about the
+gift being sent, so it doesn't stick around after we start doing
+other things.
+"""
+
+
 def showPopulation(*args):
     idxs = lbox.curselection()
-    if len(idxs)==1:
+    if len(idxs) == 1:
         idx = int(idxs[0])
         code = countrycodes[idx]
         name = countrynames[idx]
         popn = populations[code]
         statusmsg.set("The population of %s (%s) is %d" % (name, code, popn))
     sentmsg.set('')
 
-# Called when the user double clicks an item in the listbox, presses
-# the "Send Gift" button, or presses the Return key.  In case the selected
-# item is scrolled out of view, make sure it is visible.
-#
-# Figure out which country is selected, which gift is selected with the 
-# radiobuttons, "send the gift", and provide feedback that it was sent.
+
+"""
+Called when the user double clicks an item in the listbox, presses
+the "Send Gift" button, or presses the Return key.  In case the selected
+item is scrolled out of view, make sure it is visible.
+
+Figure out which country is selected, which gift is selected with the
+radiobuttons, "send the gift", and provide feedback that it was sent.
+"""
+
+
 def sendGift(*args):
     idxs = lbox.curselection()
-    if len(idxs)==1:
+    if len(idxs) == 1:
         idx = int(idxs[0])
         lbox.see(idx)
         name = countrynames[idx]
         # Gift sending left as an exercise to the reader
         sentmsg.set("Sent %s to leader of %s" % (gifts[gift.get()], name))
 
+
 # Create and grid the outer content frame
 c = ttk.Frame(root, padding=(5, 5, 12, 0))
-c.grid(column=0, row=0, sticky=(N,W,E,S))
+c.grid(column=0, row=0, sticky=(tkinter.N, tkinter.W, tkinter.E, tkinter.S))
 root.grid_columnconfigure(0, weight=1)
-root.grid_rowconfigure(0,weight=1)
+root.grid_rowconfigure(0, weight=1)
 
 # Create the different widgets; note the variables that many
 # of them are bound to, as well as the button callback.
 # We're using the StringVar() 'cnames', constructed from 'countrynames'
-lbox = Listbox(c, listvariable=cnames, height=5)
+lbox: tkinter.Listbox = tkinter.Listbox(c, listvariable=cnames, height=5)
 lbl = ttk.Label(c, text="Send to country's leader:")
-g1 = ttk.Radiobutton(c, text=gifts['card'], variable=gift, value='card')
-g2 = ttk.Radiobutton(c, text=gifts['flowers'], variable=gift, value='flowers')
-g3 = ttk.Radiobutton(c, text=gifts['nastygram'], variable=gift, value='nastygram')
+g1 = ttk.Radiobutton(c, text=gifts['card'],
+                     variable=gift, value='card')
+g2 = ttk.Radiobutton(c, text=gifts['flowers'],
+                     variable=gift, value='flowers')
+g3 = ttk.Radiobutton(c, text=gifts['nastygram'],
+                     variable=gift, value='nastygram')
 send = ttk.Button(c, text='Send Gift', command=sendGift, default='active')
 sentlbl = ttk.Label(c, textvariable=sentmsg, anchor='center')
-status = ttk.Label(c, textvariable=statusmsg, anchor=W)
+status = ttk.Label(c, textvariable=statusmsg, anchor=tkinter.W)
 
 # Grid all the widgets
-lbox.grid(column=0, row=0, rowspan=6, sticky=(N,S,E,W))
+lbox.grid(column=0, row=0, rowspan=6, sticky=(tkinter.N, tkinter.S, tkinter.E, tkinter.W))
 lbl.grid(column=1, row=0, padx=10, pady=5)
-g1.grid(column=1, row=1, sticky=W, padx=20)
-g2.grid(column=1, row=2, sticky=W, padx=20)
-g3.grid(column=1, row=3, sticky=W, padx=20)
-send.grid(column=2, row=4, sticky=E)
-sentlbl.grid(column=1, row=5, columnspan=2, sticky=N, pady=5, padx=5)
-status.grid(column=0, row=6, columnspan=2, sticky=(W,E))
+g1.grid(column=1, row=1, sticky=tkinter.W, padx=20)
+g2.grid(column=1, row=2, sticky=tkinter.W, padx=20)
+g3.grid(column=1, row=3, sticky=tkinter.W, padx=20)
+send.grid(column=2, row=4, sticky=tkinter.E)
+sentlbl.grid(column=1, row=5, columnspan=2, sticky=tkinter.N, pady=5, padx=5)
+status.grid(column=0, row=6, columnspan=2, sticky=(tkinter.W, tkinter.E))
 c.grid_columnconfigure(0, weight=1)
 c.grid_rowconfigure(5, weight=1)
 
@@ -92,13 +116,15 @@ def sendGift(*args):
 root.bind('<Return>', sendGift)
 
 # Colorize alternating lines of the listbox
-for i in range(0,len(countrynames),2):
+for i in range(0, len(countrynames), 2):
     lbox.itemconfigure(i, background='#f0f0ff')
 
-# Set the starting state of the interface, including selecting the
-# default gift to send, and clearing the messages.  Select the first
-# country in the list; because the &lt;&lt;ListboxSelect&gt;&gt; event is only
-# fired when users makes a change, we explicitly call showPopulation.
+"""
+Set the starting state of the interface, including selecting the
+default gift to send, and clearing the messages.  Select the first
+country in the list; because the &lt;&lt;ListboxSelect&gt;&gt; event is only
+fired when users makes a change, we explicitly call showPopulation.
+"""
 gift.set('card')
 sentmsg.set('')
 statusmsg.set('')