Answer to Question #104953 in Python for Chukwuma Emeli

Question

Write a Python program that does the following.

Create a string that is a long series of words separated by spaces. The string is your own creative choice. It can be names, favorite foods, animals, anything. Just make it up yourself.

Turn the string into a list of words using split.

Delete three words from the list, but delete each one using a different kind of Python operation.

Sort the list.

Add new words to the list (three or more) using three different kinds of Python operation.

Turn the list of words back into a single string using join.

Print the string.


Provide your own examples of the following using Python lists. Create your own examples. .

Nested lists
The “*” operator
List slices
The “+=” operator
A list filter
A list operation that is legal but does the "wrong" thing, not what the programmer expects

Provide the Python code and output for your program and all your examples.

Answer 1

# test string
test_string = "Hello this is a test string to convert to list"
print(test_string)

# convert to list using 'split'
print("\n converting string to list")

word_list = test_string.split(" ")
print(word_list)

print("\nremoving items 4 different ways")
# remove item using 'remove'
word_list.remove("this")
print(word_list)
# remove item using 'pop'
word_list.pop(3)
print(word_list)
# remove item using 'del'
del word_list[2]
print(word_list)
# remove item using 'filter'
word_list = list(filter(lambda x: x != "convert", word_list))
print(word_list)

# sort values
print("\n sorting")
word_list.sort()
print(word_list)

print("\n adding items 4 different ways")
# add item using 'append'
word_list.append('one')
print(word_list)

# add item using '+'
word_list = word_list + ["two"]
print(word_list)

# add item using 'insert'
word_list.insert(1, "three")
print(word_list)

# add item using 'extend'
word_list.extend(["four"])
print(word_list)

# list to string
print("\nconvert list to string")
updated_string = " ".join(word_list)
print(updated_string)

# nested lists: matrix addition
print("\nnested lists: matrix multiplication")


def print_matrix(matrix):
    for idx1 in range(len(matrix)):
        for idx2 in range(len(matrix[idx1])):
            print(str(matrix[idx1][idx2]), end=' ')
        print("")


matrix4x3_1 = [
    [4, 8, 6, 0],
    [1, 2, 3, 2],
    [0, 2, 0, 7]
]

print_matrix(matrix4x3_1)
print("")

matrix4x3_2 = [
    [2, 2, 8, 1],
    [5, 4, 8, 2],
    [5, 4, 8, 3]
]

print_matrix(matrix4x3_2)

res_matrix = []
for idx1 in range(len(matrix4x3_1)):
    row = []
    for idx2 in range(len(matrix4x3_1[idx1])):
        row.append(matrix4x3_1[idx1][idx2] + matrix4x3_2[idx1][idx2])
    res_matrix.append(row)

print("")
print_matrix(res_matrix)
print("")

# * operator for lists
print("* operator")
mul_op = ["one", "two", "three"]
print(mul_op)
mul_op = mul_op * 4
print(mul_op)

# list slice
print("\n slices")
slice_list = [1, 2, 3, 4, 5, 6, 7, 8, 9]
print(slice_list)
slice_list = slice_list[3:8]
print(slice_list)

# += operator
print("\n+= operator")
plus_op = [1, 2, 3, 4, 5]
print(plus_op)
plus_op += [0, 9, 8, 7, 6]
print(plus_op)

# filter
print("\n filtering")
nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(nums)
filtered = list(filter(lambda x: x % 2 == 0, nums))
print(filtered)

# legal but wrong
print("\nlegal operation that does the 'wrong' thing")
legal_list = [1, 2, 3]
print(legal_list)
legal_list = legal_list.append(4)
print(legal_list)