Exam 1 Flashcards
What is a “program”
An algorithm to accomplish a task
What is an “IDE”
Integrated Development Environment:
A compiler like spyder
Quality assurance
how someting is checked to make sure it works as it is supposed to
what is a unit test?
Software test that focuses on components of a program
What is a test suite and a test runner
collection of test cases to run a single job with different test scenarios
Test runner: tool that is used to run tests and export results
t or f:
false, it should contain only one assertion statement
what is TDD
test driven development:
development where software requirements are converted tot est cases before software is fully developed
what is pseudocode, why helpful
pseudocode is informal way of programming that does not require strict language syntax
can be helpful cuz more understandable
What is a module, why helpful
a file that defines a collection of useful functions and variables, usually have a common theme or purpose
helpful so no need to redefine functions or variables every time
what is a statement in a program
a command in a program that a computer understands
what is an expression
value or anything that executes and becomes a value
what are the rules for a valid variable name
1) start with a letter or underscore
2) only made of letters numbers or underscores
3) capitalized letters matter
is a==A
no
why is x = x**2 always valid
the expression updates x
what is an operand
term used to describe the data or values that are operated on by an operater
name three types and describe each of them
1) numeric (int, float, complex)
2) text sequence (string) words
3) sequence: list and range
4) binary sequence
5) plot: graphical representation of numeric data
etc…….
binary operator?
operators that require two operands at least eg +, -, *
unary operator?
operators that require one operand
only needs one operand: negative or positive
what does = do?
assigns a value to a variable
what does == do
compares two values to determine if they’re equal
what does % do
output is the remainder
waht does // do
divides and returns only integer result
eg -8//3 is -3 because answer is -2.67777… so rounds up
what will -8/3 calculate to
-3
what will 8%-3 calculate to
will be -3 because because will return a value that is the same sign as the denominator
goes in opp direction
3 * 3 = 9 so remainder is -1
3*2 = 6 so remainder is +2
relational operator?
operator that compares two values and returns true or false
what is the order of precedence in decreasing of the and, not, or
1) not
2) and
3) or
do arithmetic or relational operators have higher precedence
arithmetic
t or f: all realtional operations have the same precedence
true
what are lists
array… usually composed of same variables
how do you express the third elemnt in a list
list[2]
how would you express second to last element in a list
if list is n long,
list[n-2]
or list[-2]
given a list x = [1, 2, 3,4 ,5], what will x[2::2] return
will return [3, 5]
starts from x[2] and has step of 2
what does import do
import is used to give access to different python moduels
what does len() do
gives the elngth of an object, number of items in a list
what does .append() do
adds whatever is inside () to the end of existing array
what makes up np.linspace() command
np.linspace(start, stop, how many samples to generate).astype(int or float)
int: determines whether elements are floats or integers
what are three attrinbutes of a numpy array
- always homogenous (same data type)
- optimized for numerical and scientific computation
- can be manipulated using mathematical functions like linear algebra etc
- consumes less memory
deep copy vs shallow copy?
shallow: constructs new compound object and inserts references into the array
deep: recursively inserts copies of the og into each entry
Why indent?
indicates a block of code
how many spaces in a single indent?
4 spaces
What is the difference between a parameter and an argument?
A parameter is a placeholder for a certain type of value while an argument defines the parameter’s value
If a function does not need to return anything, what does the return expression look like
no return statement
List convention for docstring
1) first line should be short concise function summary
2) The first line should be a phrase ending in a period
3)Indent lines consistently
4) Separate lines with a blank line when needed
what is PEP
document where new features in python can be proposed
Abs Error vs Rel Error?
Abs error is the difference between measured eerror and true error
Rel error is the absoute error divided by true value (percentage)
What is the hidden bit?
gives the sign of the number
what is machine epsilon?
The difference between 1.0 and the next larger representable number
in double precision IEEE-754 , how many binary bits are used to store a real number
64 bits
1 bit for sign, 11 bits for exponent, and 52 bits for significant
What information does the sign bit give
gives the sign of the number
what information does the exponent give
Scaling factor, determines how many decimal places
What informaiton does the significand give?
fractional values, amt of sig figs
What does assert do?
Used to test a condition
assert condition, message
if condition is not true, message is raised with assertion error
what is assert best used for?
good for debugging and teesting assumptions
bad for data validation
what does [0:2] do
in a list it would slice out all entries past 1.
This is because start is inclusive while stop is excusive
Metaphor for and
switches in series
Metaphor for or
switches in parallel
The inverse of an upper triangular matrix is also an__
upper triangular matrix
What is (AB)^-1 equal to
B^-1 * A^-1
T or f: an LU decomp always exists if the matrix is square invertible without altering the matrix
False
if Q is an invertible square matrixwhat is Q.T * Q equivalent to
I
