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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Introduction to Python part VI (And a discussion of random vectors)
Activity 1
Step1:  We can access elements of a list using indices – numbered positions of elements in the list. These positions are numbered starting at 0, so the first element has an index of 0.
Step2:  Note that the elements of lists, like arrays are "mutable" or changeable after they are defined
Step3:  Exercise 1
Consider the following code
Step4:  If you print out the above what do you get for the salsa recipie?  How does this compare to the below, similar operation?
Step5:  Can you explain the difference in outputs?
Exercise 2
Step6:  Here is an example of how nested indexing works visually
Step7:  While modifying in place, it is useful to remember that Python treats lists in a slightly counter-intuitive way.
As we saw earlier, when we modified the salsa list item in-place, if we make a list, (attempt to) copy it and then modify this list, we can cause all sorts of trouble. This also applies to modifying the list using the above functions. What do you think the outputs will be from the following operations?
Step8:  Exercise 4
So far we’ve seen how to use slicing to take single blocks of successive entries from a sequence. But what if we want to take a subset of entries that aren’t next to each other in the sequence?
You can achieve this by providing a third argument to the range within the brackets, called the step size. The example below shows how you can take every third entry in a list
Step9:  Notice that the slice taken begins with the first entry in the range, followed by entries taken at equally-spaced intervals (the steps) thereafter.
What slice of beatles will produce the following output (i.e., the first character, third character, and every other character through the end of the string)?
I notpssgre ntesae
Step10:  Exercise 5
+ usually means addition, but when used on strings or lists, it means “concatenate”. Given that, what do you think the multiplication operator * does on lists? In particular, what will be the output of the following code?
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Python Code:
odds = [1, 3, 5, 7]
print('odds are:', odds)
Explanation: Introduction to Python part VI (And a discussion of random vectors)
Activity 1: Discussion of multiple random variables
How is the notion of the expected value extended into multiple variables?  What does this represent?
What is a marginal distribution / density?  How is this related to a joint distribution / density for multiple variables?
How is the marginal related to conditional probability and indepdendence?
What is an ensemble matrix?  How is this related to a sampling distribution?  How is the ensemble matrix related to the sample mean?
Activity 2: Python lists
Unlike NumPy arrays, lists are a data structure built into the base Python language so we do not have to load a library to use them. We create a list by putting values inside square brackets and separating the values with commas:
End of explanation
print('first element:', odds[0])
print('last element:', odds[3])
print('"-1" element:', odds[-1])
Explanation: We can access elements of a list using indices – numbered positions of elements in the list. These positions are numbered starting at 0, so the first element has an index of 0.
End of explanation
odds[0] = 10
print('first element:', odds[0])
Explanation: Note that the elements of lists, like arrays are "mutable" or changeable after they are defined
End of explanation
salsa = ['peppers', 'onions', 'cilantro', 'tomatoes']
my_salsa = salsa
salsa[0] = 'hot peppers'
Explanation: Exercise 1
Consider the following code
End of explanation
salsa = ['peppers', 'onions', 'cilantro', 'tomatoes']
my_salsa = list(salsa) 
salsa[0] = 'hot peppers'
Explanation: If you print out the above what do you get for the salsa recipie?  How does this compare to the below, similar operation?
End of explanation
x = [['pepper', 'zucchini', 'onion'],
     ['cabbage', 'lettuce', 'garlic'],
     ['apple', 'pear', 'banana']]
Explanation: Can you explain the difference in outputs?
Exercise 2:
Since a list can contain any Python variables, it can even contain other lists.
For example, we could represent the products in the shelves of a small grocery shop:
End of explanation
my_list = ["banana", 10, 35, "orange"]
my_list.pop()
my_list.append("orange")
my_list
Explanation: Here is an example of how nested indexing works visually:
Using the above conventions, can you extract the bag in cabbage from x? 
Exercise 3:
Two essential methods that are defined on lists are the following
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odds = [1, 3, 5, 7]
primes = odds
primes.append(2)
Explanation: While modifying in place, it is useful to remember that Python treats lists in a slightly counter-intuitive way.
As we saw earlier, when we modified the salsa list item in-place, if we make a list, (attempt to) copy it and then modify this list, we can cause all sorts of trouble. This also applies to modifying the list using the above functions. What do you think the outputs will be from the following operations?
End of explanation
primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37]
subset = primes[0:12:3]
print('subset', subset)
Explanation: Exercise 4
So far we’ve seen how to use slicing to take single blocks of successive entries from a sequence. But what if we want to take a subset of entries that aren’t next to each other in the sequence?
You can achieve this by providing a third argument to the range within the brackets, called the step size. The example below shows how you can take every third entry in a list:
End of explanation
beatles = "In an octopus's garden in the shade"
Explanation: Notice that the slice taken begins with the first entry in the range, followed by entries taken at equally-spaced intervals (the steps) thereafter.
What slice of beatles will produce the following output (i.e., the first character, third character, and every other character through the end of the string)?
I notpssgre ntesae
End of explanation
counts = [2, 4, 6, 8, 10]
repeats = counts * 2
print(repeats)
Explanation: Exercise 5
+ usually means addition, but when used on strings or lists, it means “concatenate”. Given that, what do you think the multiplication operator * does on lists? In particular, what will be the output of the following code?
End of explanation
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