# 20190914
# R. Dawes

print("\ncopying a list")
list1 = [1,2,3,4]
list2 = list1

print("list1:",list1)
print("list2:",list2)
print("\n")

list1[2] = 10000

print("list1:",list1)
print("list2:",list2)

print("\ncopying a list properly")
list1 = [1,2,3,4]
list3 = list1[:]
print("list1:",list1)
print("list3:",list3)

list1[3] = 12345
print("\n")

print("list1:",list1)
print("list3:",list3)
print("\n")

print("\nSlicing")
list1 = ['a','b','c','d','e','f','g']
list2 = list1[2:5]
list3 = list1[2:-1]
list4 = list1[:4]
list5 = list1[3:]

print("list1:",list1)
print("list2 = list1[2:5]   :",list2)
print("list3 = list1[2:-1]  :",list3)
print("list4 = list1[:4]    :",list4)
print("list5 = list1[3:]    :",list5)



print("\nuse + to join two lists and create a new list")
list1 = ['a','b','c']
list2 = [1,2,3,4]
list3 = list1 + list2
print("list1:",list1)
print("list2:",list2)
print("list3:",list3)

print("\nMore slicing")
list6 = list1[1:] + list1[0:1]
print("list6:",list6)

#note that the next line doesn't work

#list7 = list1[1:] + list1[0]

#but this does
list7 = list1[1:].append(list1[0])
print("list7:",list7)


print("\nuse extend to add all elements of one list to another list")
print("list1:",list1)
print("list2:",list2)
list1.extend(list2)
print("list1 extended by list2:",list1)

print("\nappend 'a' to list3")
list3.append('a')
print("list3:",list3)

print("\nremove 'a' from list3")
list3.remove('a')
print("list3:",list3)

print("\ndel element in position 4 in list3")
del list3[4]
print("list3:",list3)

print("\ncount the 'b's in a list")
list4 = list3+list1
print("list4:",list4)
x = list4.count('b')
print("number of b's in list4",x)

print("\nlength of list4")
print("the length of list4 is",len(list4)
)

print("\nsort a list 'in-place'")
list8 = [12,6, 9, 32, 6, 1]
print("list8:",list8)
list8.sort()
print('sorted list8',list8)

print("\nuse sorted to create a sorted copy of a list")
list9 = ["horse","dog", "cat", "rooster", "monkey"]
print("list9:",list9)
list10 = sorted(list9)
print("list9:",list9)
print("list10:",list10)

print("\ninsert a new value in position 2 of list10")
list10.insert(2,126543)
print("list10:",list10)

print("\nmake a list of lists")
list11 = [list8,list10, list3, list2]
print("list11:",list11)
print("first element of list11:",list11[0])
print("third element of second element of list11:",list11[1][2])

print("\nuse a for loop to show a list of lists")
for x in list11:
   print(x)

print("\nuse * to create a list of identical items")   
list12 = [23] * 10
print("list12:",list12)
list13 = [23,45] * 10
print("list13:",list13)
list14 = [[23,45]] * 10
print("list14:",list14)