#
# Iterative construction of strings and lists 
#
# Practice 
# 

# THE PROBLEM 
3
7
9
5
6
[3, 4, 7, 9, 5, 6]


"Kolargol"

"oa"




# Preliminary notes: 
- Presumed knowledge:
  - That practiced in pervious videos 
  - Basic structure of strings, lists
  - while loop and for loop 
  - The functions range(), length(), eval() 
  - The operators in, not in, *, +   
- Relation to tuples 
- Use only the studied material.
  In particular do not use type functions, 
  save, perhaps, for append() 


# INTRODUCTORY REMARK ABOUT THE NATURE OF
# THE FOR LOOP AND ABOUT ITS KINDS 


# NOW TO THE QUESTIONS 


# Q. 1
# Write a program that receives strings one after another, 
# until an empty string is entered. The program 
# concatenates the strings in the order of their reception, 
# and prints the resulting string. 

s = input("Please enter any string: ")
newS = ""
while s != "": 
    newS = newS + s + " "
    s = input("Please enter any string: ")
print("THe concatenated string s: ", newS)
newS = newS[:-1]    
print(newS + "-")

"chair"
"table"



# Q. 2
# Write a program that receives characters (strings
# of length 1) one after another, until the string
# stop is entered. The program prints a string 
# comprising all the entered characters, in a 
# reversed order. E.g. if the program receives the 
# characters t, then a, then c, the program prints 
# the string cat. 

c = input("Please enter any character: ")
newS = ""
while c != "stop": 
    newS = c + newS
    c = input("Please enter any character: ")
print("THe concatenated string s: ", newS)

# variation with for 
s = "ybab"
newS = ""
for c in s: 
    newS = c + newS
print("THe concatenated string s: ", newS)


# Q. 3
# Write a program that receives a string s, 
# and prints a string based on s, with no 
# character duplication. E.g. if the received
# string is abbeecdad, the printed string 
# is abecd. 

s = input("Please input any string: ")
newS = ""
for c in s: 
    if c not in newS: 
        newS = newS + c 
print("The string without duplicates is: ", newS)



# Q. 4
# Write a program that prints all odd numbers in range
# 1-100 (including 100). The numbers are printed in 
# a single line, each separated from the next with 
# a comma. 


# version 1 
newS = "" 
for i in range(1, 101): 
    newS = newS + str(i) + ", "
print(newS)


# version 2 
for i in range(1, 101): 
    print(i, end = ", ")












# Q. 5
# Write a program that receives any string. 
# Any number of spaces may appear at the beginning 
# of the string, in the middle of it, and at its end. 
# The program prints the string without leading 
# and closing spaces, and also with no double spaces. 

#s = "     Prof. Albus      Dumbledore    "
s = input("Please enter any string: ")
newS = ""
lastC = ""
for c in s: 
    if not (c == " " and (newS == "" or lastC == " ")):  
        newS = newS + c 
    lastC = c
print(newS + "-")



# Q. 6
# Write a program that produces a list
# of 10 random numbers in range 1-10. 


import random 
lst = [] 
for i in range(10): 
    lst = lst + [random.randint(1, 10)]
print(lst)

print([3, 4]  + [5])

# A WORD ABOUT + VS. APPEND

# another implementation
import random 
lst = [] 
for i in range(10): 
    lst.append( random.randint(1, 10) )
print(lst)




# Q. 7
# Write a program that receives student names 
# one after another, until the string -1 is entered. 
# The program produces a list comprising all entered
# names. Next the program receives another name 
# and checks whether it is one of the names 
# in the list. If it is not, it should be added
# to the end of the list. 

studName = input("Please enter a student's name: ")
names = [] 
while studName != "-1": 
    names = names + [studName]
    studName = input("Please enter a student's name: ")
studName = input("Please enter a student's name: ")
if studName not in names: 
    names = names + [studName]
print(names)



# Q. 8
# The readers club Ulysses accepts as members 
# only readers who have read more than 5000 
# books during the last 5 years. Write a program 
# that receives, one after another, pairs of 
# reader name and number of books s/he read 
# during the last 5 years, until the string q is entered. 
# The program produces a list including 
# the names of readers who may be 
# accepted as members of the club. 

name = input("Please input name: ")
names = [] 
while name != "q": 
    booksNum = int(input("Please input number of books: "))
    if booksNum > 5000: 
        names = names + [name]
    name = input("Please input name: ")
print(names)
    

# Q. 9
# Write a program that receives a list of temperatures.  
# The program produces a list including all 
# temperatures below 0, and a separate list 
# including all other entered temperatures. 

ts = eval(input("PLease enter a list of temperatures: "))
#print(ts)
#print(type(ts))
under0 = [] 
rest = [] 
for t in ts: 
    if t < 0: 
        under0 = under0 + [t]
    else: 
        rest = rest + [t]
print(under0)
print(rest)




# Q. 10
# Write a program that receives two lists, 
# lst1 and lst2. lst1 includes 5 integers. 
# lst2 includes all integers in range 0-4, 
# arranged in a random number. E.g.
#     lst1 = [81, 24, 12, 58, 32] 
#     lst2 = [1, 3, 2, 4, 0] 
# The program scans the numbers in lst2, 
# using them as indices to lst1, and 
# for printing the numbers it includes. :
# Thus for the example lists the program prints
# the the numbers in lst2 in the following order:
# 24, 58, 12, 32, 81


lst1 = [81, 24, 12, 58, 32] 
lst2 = [1, 3, 2, 4, 0] 
for ind in lst2: 
    print(lst1[ind])



Q. 11
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 = [7, -3, 0, 0, 0, 5, -1]
lst = eval(input("Please enter any list of integers: "))
#[-3, -1, 0, 0, 0, 7, 5]
negatives = [] 
zeros = [] 
positives = [] 
for num in lst: 
    if num > 0: 
        positives = positives + [num]
    elif num < 0: 
        negatives = negatives + [num]
    else: 
        zeros = zeros + [num]
newLst = negatives + zeros + positives 
print(newLst)


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

-3
-1 -3 
-1 -3 0 10