# examples for Lists

# Tracing through code
print("---- Tracing through code ----")
num = 5
grades = [97, 86, 91, num, 88]
num = 33
big = [23, grades, num, 7]
grades[1] = 87
grades.append(6)
print("grades =", grades)
big[2] = grades
print("big =", big)

print()  # print an empty line to separate sets of examples

# Creating Lists
print("---- Creating Lists ----")
animals = ['cow', 'dog', 'horse']	# create a new list
print("animals =", animals)

animals1 = [] 					    # create an empty list
print("animals1 =", animals1)

animals1 = ['cow', 'horse']
animals2 = ['dog']
animals3 = animals1 + animals2	    # concatenate lists
print("animals3 =", animals3)


# Accessing Items in Lists
print("---- Accessing Items in Lists ----")
animals = ['cow', 'dog', 'horse']	# create a new list

print("There are", len(animals), "items in the list")

print("animals[2] =", animals[2])      # access a particular item
animals[2] = 'duck'	   # update a particular item
print("updated animals[2] =", animals[2])

print("animals[0] =", animals[0])    # indices start from zero
print("animals[-1] =", animals[-1])	 # negative numbers start from the end of the list
print('The ' + animals[0] + ' and the ' + animals[2] +  ' sleep in the barn.')


# Adding Items to Lists
print("---- Adding Items to Lists ----")
animals = ['cow', 'dog', 'horse']	# create a new list
animals.append('deer')		# add item to the end of the list
print(animals[2])			# access a particular item
animals[2] = 'duck'			# update a particular item
print(animals[0])			# indices start from zero
print(animals[-1])			# negative numbers start from the end of the list
print('The ' + animals[0] + ' and the ' + animals[2] +  ' sleep in the barn.')
animals.insert(2, 'pig')    # insert element to a particular position of the list
print(animals)


# Removing Items from Lists
print("---- Removing Items from Lists ----")
animals = ['cow', 'dog', 'horse', 'sheep', 'pig']
print(animals)

del animals[3]				# delete an element, by index
print(animals)

animals.remove('horse')		# remove a particular element, by value
print(animals)


# Length of Lists
print("---- Length of Lists ----")
animals = ['dog', 'cat', 'bird']
counter = 0
while counter < len(animals):
    print(animals[counter])
    counter += 1
print(animals)

print()

print("---- index() ----")
int_lst = [1, 2, 3]
str_lst = ['1', '2', '3']
print(int_lst.index(2))
print(str_lst.index('2'))
# print(str_lst.index(2))  # error, why?

print()

# in keyword
print("---- in keyword ----")
lst = [5, 7, 9, 11, 15]
print(7 in lst)
print(3 in lst)
print(3 not in lst)

print()

# Slicing and returning part of a list with [ : ]
print("---- slicing with [ : ] ----")
lst = [5, 7, 9, 11, 15]
print(lst)
print(lst[1:4])
print(lst[1:])
print(lst[:4])
print(lst[:-1])
print(lst[1:-2])
print(lst[2:4])
print("type of sliced list =", type(lst[2:4]))

print()

# Sorting and Reversing
print("---- Sorting and Reversing ----")
animals = ['cow', 'dog', 'horse', 'sheep', 'pig']
animals.sort()
print('sorted animals =', animals)
print('sorted animals = ' + str(animals)) 	# another way to print (notice a space after "=")

animals.reverse()
print('reversed animals = ', animals)

print()

# Two Dimensional list (list of lists)
print("---- Two Dimensional list (list of lists) ----")
lst1 = [5, 7, 9, 11, 15]
twoD_lst = [['cow', 'horse'], ['list'], [], [4, 5, 6], lst1]

print(twoD_lst)
print("the 0th item of twoD_lst =", twoD_lst[0])		    # access a particular list
print("the 1st item of the 0th item of twoD_lst =", twoD_lst[0][1])		# access a particular item

print("len of twoD_lst =", len(twoD_lst))
print("len of 1st item of twoD_lst =", len(twoD_lst[1]))

print()
print('iterate 2D list with nested for loops')
# iterate 2D list (there are many possible solutions)
row = ""
cnt = 0
# for each inner list
for item in twoD_lst:
    # iterate an inner list
    for inner_item in item:
        # form string to print
        row += str(inner_item) + " "
    print("  twoD_lst[" + str(cnt) + "] =", row)
    row = ""   # reset so there'd be no left over
    cnt += 1   # just to make the output easy to read

print()

# More examples
print("---- More examples ----")
letters = ['A', 'B', 'C']
numbers = [1, 2, 3]

# concatenate lists of different element type
both = letters + numbers
print("concat " + str(letters) + " and " + str(numbers) + " = " + str(both))   # notice casting

# letters, numbers, and both are lists.
# here, we tried to mix strings and print lists, so casting is needed
# if we simply print a list, for example print(both), casting is not needed

print(letters * 3) 		# repeat lists

del both[3] 			# delete a particular item (by index)
both.remove('B')		# remove by item
print(both)

print()

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

print("---- create a copy of a list ----")

# Create a copy of a list
import copy
animals = ['cow', 'horse', 'sheep', 'dog', 'chicken']
animals2 = animals
animals.append('goat')
animals3 = copy.copy(animals)
animals3.append('farmer')

print(animals3)
print(animals)

print()
print("---- sort() and reverse() ----")

animals.sort()
print('sorted animals = ', animals)

animals.reverse()
print('reversed animals = ', animals)

print()
print("---- create a list from a user's inputs ----")
# Create a list from a use's inputs
names = []
names.append(input("Give me a name: "))
names.append(input("Give me another name: "))
print(names)

print()
print("---- max, min(), sum() of list of numbers ----")
# max, min, sum
list1 = [12, 14, 6.0, 7, 10.5]
print("given list1 =", list1)
print("max(list1)=", max(list1))
print("min(list1)=", min(list1))
print("sum(list1)=", sum(list1))

print()
print("---- max(), min(), sum() of list of characters")
list2 = ["x", "y", "a", "b"]
print("max(list2)=", max(list2))
print("min(list2)=", min(list2))
# print("sum(list2)=", sum(list2))  # error, why?

print()
print("---- max(), min(), sum() of list of mixed types ----")
list3 = ["x", 12, 6.0, "b"]
# print("max(list3)=", max(list3))  # error, why?
# print("min(list3)=", min(list3))  # error, why?
# print("sum(list3)=", sum(list3))  # error, why?