Three_ways_to_list

# Three_ways_to_list written by ken Adams
# Explores the use of list to make teams of players. There are three parts to the program.
#Each part does something different
#Part one makes two teams using shuffle and pop
#Part two makes three teams using sample and modulus
#Part three makes three teams using sample, modulus and a while loop checks for an empty string
# code is well annotated and extra print statements show what is happening

############################################## imports ########################3
from random import choice # adds the choice function from the random library
from random import shuffle
from random import sample

#####################################Two teams using shuffle and taling an item off either end of players list###
print("PART ONE MAKES TWO TEAMS USING SHUFFLE AND POP\n")
# test data:four list two with an even number of items and two odd
players = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R']# 18 players
#players = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O','P','Q']# 17 players
#players = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O','P']# 16 players
#players = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O']# 15 players
#players = ['Harry', 'Ginny']# should only work once
#players = ['Harry'] # cannot work, in fact teamA and teamB are empty
teamA =[]
teamB = []
shuffle(players)# randomly suffle the list
print("Printing the shuffled players list.")
print("shuffled players")
print(players)
# as long as there is more than one player in the list we take a player from each side
while len(players) >1:
    teamA.append(players[0])# take the first one
    teamB.append(players[-1])# take the second one
    players.pop(0)# removing from the players list using pop
    players.pop(-1)# remove the last one
    # players is now two items shorter
    # If there was an odd number of players the middle one does not get to play

print("Below are players, teamA and teamB. Note: players is now an empty list")
print(players)
print(teamA)
print(teamB)
##############################3end of shuffle and pop ###############
print("\nPART TWO MAKES THREE TEAMS USING SAMPLE AND MODULUS\n")
# We want three teams of four player from the players2 list
players2 = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R']
chosen2 = sample(players2,12)
teams2 = [ [], [], [] ]# sets up an empty list of three empty lists

for x in range(len(chosen2)):# looping over the chosen2 list
    teams2[x%3].append(chosen2[x])# % is the modulus function it runs 0,1,2,,0,1,2,,etc
    # each item of chosen2 is allocated to one of the teams
    #each sub-list of teams will have 4 members as 12 divides 3 is 4 exactly
print("We print the items in chosen2")
print(chosen2)
print("Now we print teams 0,1, and 2")
print(teams2[0])
print(teams2[1])
print(teams2[2])
#################################### using a while loop and checking for an empty list #######
print("\nPART THREE MAKES THREE TEAMS USING SAMPLE, MODULUS AND A WHILE LOOP CHECKS FOR AN EMPTY STRING\n")
# These are copies of the lists above,
players3 = ['A', 'B', 'C', 'D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R']
chosen3 = sample(players3,12)# we want three teams of four so we randonly select twelve players
teams3 = [ [], [], [] ] # empty list of lists
print("Printing chosen3")
print(chosen3)

x = len(chosen3)-1 # x is set to the hightst index in the chosen3 list
# we continue removong the last item in chosen3 and appending it to a team, stopping when chosen3 is empty
while len(chosen3) !=0: # an empty list has length zero
    print("x value " +str(x) + " length at chosen at start of while "  +str(len(chosen3)))#optional
    teams3[x%3].append(chosen3[x])# % is the modulus function, %3 converts a number to 0, or 1 or 2
    chosen3.remove(chosen3[x])# removes the item from chosen 3, now lwn(chosen3) is one less
    x = x-1 # so we make x one less as well
print("\nThese are the three teams")
for x in range(3):
    print(teams3[x])

#######################################

print("bye")