Python

Question 1

What are the two modes you can run Python on?

Answer 1

Standard and interactive mode.

Question 2

What environments does Anaconda uses?

Answer 2

Jupyter and Spyder

Question 3

What are the three charactestic of each object in Python:

Answer 3

1) Type: determines the operations it can support
2) Value
3) Identity: an identity number for the object.

Each object has attributes (separated by dot, data attribute (value) or methods (functions)).

Question 4

What is an instance?

Answer 4

An occurrence of an object

Question 5

x.shape: (a data attribute)

Answer 5

Give you the amount of elements in an array.

Question 6

How do you distinguish from data attribute and method?

Answer 6

Method is followed by parentheses x.mean()

Question 7

What happens when you run the import statement

Answer 7

1) Create a new namespace for all the objects in the module
2) Execute the code of the module and run it in the new namespace
3) Creates a name for referencing the new namespace.

Question 8

dir(str):

Answer 8

Give the list of methods for the object in question

Question 9

True or False

Answer 9

True

Question 10

True and False

Answer 10

False

Question 11

What is a sequence in python?

Answer 11

A collection of objects in order (list, tuple, range)

Question 12

Why are list methods “In place” methods?

Answer 12

They modify the original list, they do not return a new list.

Question 13

What is polymorphism in python?

Answer 13

The operator ouput depends on the type of object it is applied to (think addition between string vs addition between numbers, a plus sign between string means concatenation).

Question 14

What is the span of a pair of vector?

Answer 14

It is the set of all their linear combinations.

Question 15

What does it mean that two or three vectors are linearlydependent?

Answer 15

One of them is redudant, you could remove one of them without reducing the span of the vectors (in other word they are sitting on the same line or on the same plane in 3D)

Question 16

What are the two properties of a linear transformation?

Answer 16

All lines must remain lines and the origin must remain fixed in space. It maintains grid lines parallel and evenly spaced.

Question 17

What are the two kinds of copies?

Answer 17

1) Shallow
2) Deep (also create the copy of the objects and references to the objects)

Question 18

List the statements:

Answer 18

Return
Import
Pass

Question 19

What are compounds statement?

Answer 19

Contains other statements and control their execution, span multiple lines. They consist of one or more clauses and a block (or suited) indented code that fall under the header.

Question 20

What is a unit vector?

Answer 20

It is a vector with all elements equal to zero, except one element which is equal to one.

Question 21

What is a sparse vector?

Answer 21

A vector is said to be sparse if many of its entries are zero; its sparsity pattern is the set of indices of nonzero entries

Question 22

What is the sum of two vectors?

Answer 22

Two vectors of the same size can be added together by adding the corresponding
elements, to form another vector of the same size, called the sum of the vectors.
Vector addition is denoted by the symbol +.

Question 23

What are universal function in numpy?

Answer 23

A universal function, or ufunc, is a function that performs element-wise operations on data in ndarrays. You can think of them as fast vectorized wrappers for simple functions that take one or more scalar values and produce one or more scalar results.

Many ufuncs are simple element-wise transformations, like numpy.sqrt or numpy.exp.

These are referred to as unary ufuncs. Others, such as numpy.add or numpy.maximum, take two arrays (thus, binary ufuncs) and return a single array as the result.

Question 24

What is vectorization?

Answer 24

This practice of replacing explicit loops with array expressions is referred to by some people as vectorization.