PART I: Basic Python Programming

Question 1

What are the different types of basic operations we can do?

Answer 1

Addition
Subtraction
Multiplication
Division
Raising x to the power of y (**)
Integer division rounded down to the nearest integer (//)
Modulo (remainder after x is divided by y) (%)

Question 2

What are modifiers?

Answer 2

Useful tricks that allow you to make changes to a variable

Question 3

What are some examples of modifiers?

Answer 3

x += 1, x -=1, etc
We can also assign multiple variables with values in a single statement
x,y,z = 1,2,3 gives x=1, y=2, z=3
x,y = 2*8-14, 5/(3**2)

Question 4

What are the common functions in the math package?

Answer 4

Exponential and logarithmic (log, log10, exp)
Trig (sin, cos, tan, asin, sinh, etc)
Other functions (sqrt)

Question 5

What is a module?

Answer 5

A sub-package

Question 6

What’s an example of a module and how do you call it?

Answer 6

Linalg

from numpy.linalg import fncname

Question 7

What should pseudo code look like?

Answer 7

Keep the same structure as code

Question 8

Lists

Answer 8

• stores comma separated values enclosed by square brackets
• elements can be of any variable type
• we can append/delete values as required

Question 9

Arrays

Answer 9

• stores a fixed number of elements, so we can’t append/delete elements
• elements must be of the same variable type
• can be multi-dimensional
• we can do arithmetic with them

Question 10

What special operations can we do with lists?

Answer 10

Sum: returns sum of elements if same type
Max: returns max value
Min: returns min value
Len: returns # of elements
List(map(operation,r)): applies arithmetic operation to all elements of list
Loadtxt(“file_name.txt”,float): loads values from text file to list

Question 11

How do we create an array?

Answer 11

• numpy package
• use sin, esp, etc from numpy bc it works on arrays rather than scalars
• zeros: array of all zeros
• ones: array of all ones
• empty: arbitrary initial values
• array: converts list into array
• array([[],[]],type) to create an array

Question 12

What special operations can we do with arrays?

Answer 12

Size: gives number of elements in array
Shape: gives rows x columns

Question 13

Slicing

Answer 13

R is list
R[m:n] gives list of values from m inclusive to n exclusive
A is array
A[2:4,3:6] gives 2D array of size 2x3 of values from A[2,3] up to and not including A[4,6]
: refers to whole row or column
R[:] gives whole list
A[:,1] gives values in 2nd column

Question 14

What’s the syntax required to create a user defined function?

Answer 14

def function_name(p1, p2, ...):
(Indent all the below lines)
Need to return a value
Don't need to return if it has that built in (like print or smth)

Question 15

What is a local variable?

Answer 15

A variable that exists only within a user defined function

It won’t affect values on the outside