this code its to confusing

# Step - 1: Variable 'all_restaurants' is created with list of restaurant names. This is straight forward.
all_restaurants = [
    "Taco City",
    "Burgertown",
    "Tacovilla",
    "Hotdog station",
    "House of tacos",
 ]

# Step - 2: Defined a function name 'tacos_only' and passed a single argument to the function 'all_restaurants' in function parameter 'restaurants'.
     def tacos_only(restaurants):
# Step - 3: Confusing part is here, so what we need to do now is we want to remove the restaurants from the 
# 'all_restaurants' list by using the '.remove()' method. If I try to remove the restaurants from the all_restaurants list by iterating through each element then indexing gets changed. see below how it works:
# What I did is I have added the "Mc Donalds' at index 1. See how it works without copy as below
all_restaurants = [
    "Taco City", # index: 0
    "Mc Donalds", # index: 1
    "Burgertown", # index: 2
    "Tacovilla", # index: 3
    "Hotdog station", # index: 4
    "House of tacos", # index: 5
 ]

# I will run a for loop to loop over all the element in the list so now

Iteration - 1: At index = 0
taco_joint = "Taco City"
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
It found taco in the string "Taco City" so it will not remove the string

Iteration - 2: At index = 1
taco_joint = "Mc Donalds"
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
Did'nt found "taco" in string "Mc Donalds" so remove the element "Mc Donalds" from index 1. So when it removed the "Mc Donalds" list element gets shifted so 'all_restaurants' looks like below:

all_restaurants = [
    "Taco City", # index: 0
    "Burgertown", # index: 1
    "Tacovilla", # index: 2
    "Hotdog station", # index: 3
    "House of tacos", # index: 4
 ]

Iteration - 3: Now if I loop through the new all_restaurant list it will skip through the "Burgertown" resides at index 1. So it will never check the if condition for 'Burgertown'
at index 2
taco_joint = "Tacovilla"
for taco_joint in all_restaurants:
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
if found "taco" in string name "Tacovilla" so it was not remvoed.

O/p: ['Taco City', 'Burgertown', 'Tacovilla', 'House of tacos']

To resolve this, we create a 2 copy of the list "all_restaurants" and assigned it to variable "taco_joints" 
          1). First copy is to remove the element from the list
          2). Second copy is to only iterating over the list
         taco_joints = restaurants.copy() # this is the first copy from which we only remove the elements
      for taco_joint in taco_joints.copy(): # this is the second copy from which we only loop over the elements
        if "taco" not in taco_joint.lower():
            taco_joints.remove(taco_joint)
       return taco_joints

dinner_options = tacos_only(all_restaurants)

all_restaurants = [
    "Taco City", # index: 0
    "Mc Donalds", # index: 1
    "Burgertown", # index: 2
    "Tacovilla", # index: 3
    "Hotdog station", # index: 4
    "House of tacos", # index: 5
 ]

taco_joints = all_restaurants.copy()
      for taco_joint in taco_joints.copy():
        if "taco" not in taco_joint.lower():
            taco_joints.remove(taco_joint)

Iteration - 1: Loop over the second copy of the list
At index = 0
taco_joint = "Taco City"
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
It found taco in the string "Taco City" so it will not remove the string

Iteration - 2: Loop over the second copy of the list
At index = 1
taco_joint = "Mc Donalds"
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
Did'nt found "taco" in string "Mc Donalds" so remove the element "Mc Donalds" from index 1 from "taco_joints" list (first copy of the list). So when it removed the "Mc Donalds" list element gets shifted so 'taco_joints' looks like below:

taco_joints = [
    "Taco City", # index: 0
    "Burgertown", # index: 1
    "Tacovilla", # index: 2
    "Hotdog station", # index: 3
    "House of tacos", # index: 4
 ]

Notice here second copy of the 'taco_joints' remain unchanged and no element shifted.

Iteration - 3: Loop over the second copy of the list 
Now if I loop through the list 'taco_list.copy()' (second copy of the list) it will not skip through the "Burgertown" resides at index 1. So it will check the if condition for 'Burgertown'
at index 2
taco_joint = "Burgertown"
for taco_joint in all_restaurants:
    if "taco" not in taco_joint.lower():
        all_restaurants.remove(taco_joint)
No taco in Burgertown it will not remove