#
# Changes in lists 
#
# Practice 
#

Preliminary notes: 
- Based on Chapter 6   
  [ ] for assignment,
  del, 
  append(), extend(), insert(), remove(), sort() 
- Required knowledge: Chapters 1-6  
- On the surface: toolbox; yet much more 
- Use only studied material. 


# Rational 
Given a string, replace all spaces 
with a comma.

s = "a b c" 
s[1] = ','

# 1  
s = "a b c" 
newS = ""
for c in s: 
    if c != " ": 
        newS = newS + c 
    else: 
        newS = newS + ","
print(newS)
print(s)

# 2 
s = "a b c" 
newS = s.replace(' ', ',')
print(newS)
print(s)




# Q. 1
# Write a program that receives a list 
# of integers and replaces all integers 
# greater than 99 by "NA". 

lst = [5, 150, -32, 250, 0]
for i in range(len(lst)): 
    if lst[i] > 99: 
        lst[i] = "NA"
print(lst)
        






# Q. 2
# Write a program that given the following list: 
# [ ['ID', 1, 2, 3, 4], 
#   ['GENDER', 1, 1, 2, 1], 
#   ['INCOME', 5326, 2136, 7632, 6661] ]
# which represents the following table: 
#     ID GENDER INCOME
#      1      1   5326
#      2      1   2136
#      3      2   7632
#      4      1   6661 
# adds 100 to the income of all GENDER == 2. 


table = [ ['ID', 1, 2, 3, 4], 
        ['GENDER', 1, 1, 2, 1], 
        ['INCOME', 5326, 2136, 7632, 6661] ]
for i in range(len(table[1])): 
    if table[1][i] == 2: 
        table[2][i] = table[2][i] + 100
print(table)
        



# Q. 3 
# Write a program that receives 10 integers 
# in range 1-5. The program finds how many times
# each number in the range was entered. 

nums = [0] * 5
for i in range(10): 
    num = int(input("Please enter an integer in range 1-5: "))
    nums[num - 1] = nums[num - 1] + 1     
print("Number of 1 entered is:", nums[0])
    



# Q. 4 
# Which name should Yasmin give her daughter, 
# (1) Su, (2) Sun, (3) Suny, (4) or Sunia? 
# Write a program that iteratively receives a number in 
# range 1-4 indicating a name, until q is entered. 
# The program then prints the name which was 
# chosen the greatest number of times. 

names = ['Su', 'Sun', 'Suny', 'Sunia']
counts = [0] * 4
num = input("Please enter your choice 1-4: ")
while num != 'q': 
    choice = int(num)
    counts [choice - 1] = counts [choice - 1] + 1 
    num = input("Please enter your choice 1-4: ")
print(counts)
print(names[counts.index(max(counts))])




# Q. 5 
# Which destination should Dan choose for 
# holiday: (1) Paris, (2) London, (3) Tokyo 
# or (4) Berlin? Write a program that receives 
# a number in range 1-4 indicating a destination, 
# and the number of points the user gives it, 
# until q is entered. The program then prints 
# the destination that received the greatest 
# number of points. 
# Challenge: what would we do if the 
# points were multiplied and not added? 

names = ['Paris', 'London', 'Tokyo', 'Berlin']
sums = [0] * 4
num = input("Please enter your choice 1-4: ")
while num != 'q': 
    choice = int(num)
    points = int(input("Please enter number of points: "))
    sums [choice - 1] = sums [choice - 1] + points
    num = input("Please enter your choice 1-4: ")
print(sums)
print(names[sums.index(max(sums))])







# Q. 6 - append() 
# Write a program that produces a list of 
# 10 random numbers in range 5-15. 

# with + 
import random 
lst = [] 
for i in range(10): 
    lst = lst + [random.randint(5, 15)]
print(lst)

# with append()     
import random 
lst = [] 
for i in range(10): 
    lst.append(random.randint(5, 15))
print(lst)

Comprensions 

lst = [random.randint(5, 15) for i in range(10)]



# A note on list comprehension




# Q. 7 - extend() 
# Write a program that receives lists of 
# pairs of integers until q is entered. 
# THe program produces a list including 
# all the integers in the list. 

lst = [] 
yourLst = input("Please enter a list of two integers: ")
while yourLst != 'q':     
    lst.extend(eval(yourLst)) 
    yourLst = input("Please enter a list of two integers: ")
print(lst)







# Q. 8 - insert() 
# Write a program that receives a list of 
# integers and rearranges it such that 
# all negative integers come before 0, 
# which itself comes before all positive
# integers. 

#lst = eval(input("Please enter any list of integers: "))
lst = [-3, -1, 10, 0, 0, -7, 5]
newLst = [] 
negNum = 0 
for num in lst: 
    if num > 0: 
        newLst.append(num)
    elif num < 0: 
        newLst.insert(0, num)             
        negNum = negNum + 1
    else: 
        newLst.insert(negNum, 0)     
print(newLst)

           
# Q. 9 - del
# Write a program that given a list of integers, 
# deletes all integers greater than 50. 

lst = [100, 20, 30, 70]
newLst = [] 
for num in lst: 
    if num <= 50: 
        newLst.append(num)
print(newLst)

lst = [100, 20, 30, 70]
i = 0 
while i < len(lst) :
    print("i = ", i, lst, "len =", len(lst))
    if lst[i] > 50: 
        del lst[i]
    else: 
        i = i + 1
print(lst)




# Q. 10 - remove() 
# Write a program that given a list of 
# integers, removes all duplicates. 

lst = [5, 5, 5, 8, 8, 3, -1, -1, -1, 5]
for num in lst: 
    while lst.count(num) > 1: 
        lst.remove(num)
print(lst)

# old solution 
lst = [5, 5, 5, 8, 8, 3, -1, -1, -1, 5]
newLst = [] 
for num in lst: 
    if num not in newLst: 
        newLst.append(num)
print(newLst)    




Q. ? - sort()
The following string contains the text of the 
first sentence in James Joyce-s Ulysses. 
sent = "Stately, plump Buck Mulligan came from the stairhead, bearing a bowl of lather on which a mirror and a razor lay crossed. A yellow dressinggown, ungirdled, was sustained gently behind him on the mild morning air. He held the bowl aloft and intoned:"
find the most freqent letter in this sentence. 

import string
sent = "Stately, plump Buck Mulligan came from the stairhead, bearing a bowl of lather on which a mirror and a razor lay crossed. A yellow dressinggown, ungirdled, was sustained gently behind him on the mild morning air. He held the bowl aloft and intoned:"
freqs = [] 
for c in sent.lower(): 
    if c != " " and c not in string.punctuation: 
        freqs.append([sent.count(c), c])
freqs.sort(reverse = True)
print(freqs[0])


print(string.punctuation)