#
#   modifying list.
#
list_1 = [0,10,20,30,40,50,60,70,80,90]
print(f"list_1: {list_1}")

# Modify elements and slices.
list_1[3]=5
print(f"list_1 after 'list_1[3]=5': {list_1}")
list_1[0]=2
print(f"list_1 after 'list_1[0]=2': {list_1}")

list_1[5:8]=[15,16,17]
print(f"list_1 after 'list_1[5:8]=[15,16,17]': {list_1}")
list_1[3:1:-1]=[61,62]
print(f"list_1 after 'list_1[3:1:-1]=[61,62]': {list_1}")

list_1 = [0,10,20,30,40,50,60,70,80,90]
print(f"list_1: {list_1}")
print("""\nTry to execute: list_1[10]=3
list_1[10]=3
Traceback (most recent call last):
  File "....", line 12, in <module>
    list_1[10]=3
IndexError: list assignment index out of range
""")
list_1.append(100)
print(f"list_1 after 'list_1.append(100)': {list_1}")
print()
print("""append() takes only one argument:
list_1.append(110,100,110,100)
print(f"list_1 after 'list_1.append(110,100,110,100)': {list_1}")
Traceback (most recent call last):
  File "....", line 30, in <module>
    list_1.append(110,100,110,100)
TypeError: list.append() takes exactly one argument (4 given)
""")
print("This also may not be what one has in mind.")
list_1.append([110,100,110,100])
print(f"list_1 after 'list_1.append([110,100,110,100])': {list_1}")
print()
print(f"Instead, use extend()")
list_1.extend([110,100,110,100])
print(f"list_1 after 'list_1.extend([110,100,110,100]))': {list_1}")

list_1.insert(2,79)
print(f"list_1 after 'list_1.insert(2,79))': {list_1}")
del list_1[3]  # del: statement; 
    # len(list_1): function.
    # list_1.insert(...): method: a function of an object
print(f"list_1 after 'del list_1[3])': {list_1}")
del list_1[0:2]
print(f"list_1 after 'del list_1[0:2])': {list_1}")
list_1.remove(100)
print(f"list_1 after 'list_1.remove(100)': {list_1}")
list_1.remove(100)
print(f"list_1 after 'list_1.remove(100)': {list_1}")
pop_result = list_1.pop()
print(f"list_1.pop() returns {pop_result}")
print(f"list_1 after 'list_1.pop()': {list_1}")