Problem solving final exam guide, Summaries of Physics

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C. Conn, R. McLean,

Problem solving final exam guide

FINALS EXAM STUDY GUIDE

Algorithm

• Methodical step-by-step procedure to perform a task Task decomposition
• Process of breaking a complex task into smaller parts Statement
• Program instruction, consists of a series of statements Argument
• Any piece of data that is passed into a function when it is called Parameter
• Variable that receives an argument Expression
• Code that returns a value, a * b = 10 Variables
• Named references to values stored by the interpreter String literal
• Text endorsed in quotes Newline character
• \n, within a string literal Type
• Determines how a value can behave Assignment operator
• = Identity
• A unique identifier that describes the object, also called name Keywords
• reserved words that are already in Python

Loop variable

• Variable used to count the number of iterations Range
• range(5) - > 0- 4
• range(0,5) - > 0- 4
• range(0,5) - > 0 , 1 , 2 , 3 , 4
• range(0,5,2) - > 0 , 2 , 4
• range(5,0,-1) - > 5 , 4 , 3 , 2 , 1
• range(5,0,-2) - > 5 , 3 , 1 For loop
• Number of iterations is computable, looking for a specific # of iterations While loop
• Checking the truth value Nested loop
• Loop that appears as part of the body of another loop Break
• Causes an immediate jump to the while / for loop reader statement Return statement
• Used to return one output value None
• Special keyword that indicates no value Pass
• Placeholder, performs no operation Index
• Position of a character, starts from 0, use [] String concatenation
• “New” + “York”

Slice notation

• str [ 0 : 2 ] - > value @ 0 , value @ 1
• str [ 8 : ] - > value @ 8 until value @ end
• str [ : - 1] - > all but the last character
• str [ : ] - > everything Replace
• replace (old , new)
• replace (old , new , count) Find
• find(x) - > returns position of first occurence
• find(x , start) - > returns position but begins at start
• find(x , start , end) - > returns position but within start and end Count
• count(x) - > returns the number of times it occurs Strip
• str.strip(a) - > return a copy with all a remove List
• Container that contains references, [] Element
• Item in a list, can be any type Append
• .append(x) - > adds x to the end of the list Insert
• .insert(i , x) - > inserts x in the specific i indicated Pop
• .pop() - > removes the last item of the list
• .pop(1) - > removes the item in index 1 Remove
• .remove(‘abc’) - > removes the first element whose value is ‘abc’

my_list[start : end : stride] Tuples

• Immutable, () Unpacking tuples
• me = (‘Alex’ , “Burton” , 19) - > (first name , last name , age) Lists w/ tuples
• people = [(“Alex” , 19) , (“Eva” , 20)]
• student_name , age = people[1] Dictionary
• Another type of container object, {}
• Lists are associated w/ index, dictionaries are associated w/ key {key : value}
• Keys have to match exactly Indexing dictionary
• contacts = {“Alan‘ : “19” , “Patrick” : “20”}
• ages[“Alan”] - > “19” Adding to a dictionary
• ages[“Liam”] = “20” Overwriting a key
• If key already exists in a dictionary, then the value is changed .values()
• Checks all the values in the dictionary
• For phone_number (value) in contacts.keys(): (name of dictionary) Nested dictionaries
• dictionary = {“Neal” : {“office” : “vec 405” , “dept” : “cecs”}}
• dictionary [“Neal”] [“office”] PRACTICE MCQs VARIABLE NAMES

1. Is Python case sensitive when dealing with identifiers? a. yes b. no c. machine dependent d. none of the mentioned i. a) - > Case is always significant.
2. What is the maximum possible length of an identifier? a. 31 characters b. 63 characters c. 79 characters d. none of the mentioned i. d) - > Identifiers can be of any length.
3. Which of the following is invalid? a. _a = 1 b. __ a = 1 c. str __ = 1 d. none of the mentioned i. d) - > All the statements will execute successfully but at the cost of reduced readability.
4. Which of the following is an invalid variable? a. my_string_ b. 1st_string c. Foo d. _ i. b) - > Variable names should not start with a number.
5. Why are local variable names beginning with an underscore discouraged? a. they are used to indicate private variables of a class b. they confuse the interpreter c. they are used to indicate global variables d. they slow down execution i. a) - > As Python has no concept of private variables, leading underscores are used to indicate variables that must not be accessed from outside the class.
6. Which of the following is not a keyword?