Python Final Exam, Python- Midterm 2
how do you access an element of a string?
index of the element surrounded by square brackets example: hello_str= 'example' print(hello_str[1]) prints e
what is a computer?
a digital electronic machine that can be programmed to carry out sequences of arithmetic or logical operations automatically
what is a breakpoint?
a line number of interest in your program when the debugger is running, it halts execution of the program at this line
what is the definition of an index?
a location in the sequence of a particular element; positive values count up from the left beginning with index 0 and negative values count down from the right beginning with -1
what does it mean that a sequence is iterable?
a loop can iterate through each element of a sequence in order, meaning it moves character by character
what is a variable?
a name we designate to represent an object in our program
what is deep copy?
a new object and recursively adds the copies of nested objects present in the original elements
what is shallow copy?
a new object is created which store the top level reference of the original element
what is an algorithm?
a process or set of rules to be followed in calculations or other problem-solving operations
what is a string function?
a program that performs some operation takes an argument and returns a value based on the argument and the function's operation
what is a string?
a sequence of characters indicated by quotation marks; the exact sequence of characters is maintained
what is a program?
a sequence of instructions
what is a program?
a sequence of instructions that are converted into binary commands for the processor to understand
what is a method?
a sequence of steps that describes how to solve a problem
what is a string method?
a variation on a function that is applied in the context of a particular object indicated by dot notation invocation ex: my_str.upper( ) = upper case string
what is slicing?
ability to select a subsequence of the overall sequence
what does insert( ) do?
adds the new element specific value in the specific position
what does append( ) do?
adds the new element to the end of the list
what are pre-code planning tools?
algorithms flowcharts pseudocode
what is a binary file?
all the information is taken directly without translation, not readable
what is a selection statement?
allows a program to test several conditions and execute instructions based on which condition is true
what does 'continue' mean for debugging?
an action to take in the debugger that will continue execution until the next breakpoint is reached or the program exits
what does 'stepover' mean for debugging?
an action to take in the debugger that will step over a given line if the line contains a function, the function will be executed and the result returned without debugging each line
what is an exception?
an event that occurs during the execution of a program that disrupts the normal flow of the program's instructions in general, when script encounters a situation that it cannot cope with represents an error
what does it mean for an operation to be overloaded?
an operation can perform multiple things depending on what type of element is working with the operator + is overloaded because it can concatenate or add depending on if there's integers or strings
what does the 'in' operator do?
checks to see if a substring exists within a string if it doesn't exist: returns false if it does exist: returns true my_str = 'abc' 'a' in my_str returns true
what is 'w' mode?
clears the file's contents and is write-only creates and opens a new file if the file doesn't exist
what is 'w+'?
clears the file's contents and writes at the beginning of the file creates and opens a new file if one doesn't exist
what should you always do at then end of using a file?
close it using file.close( ) flushes the buffer contents from the computer to the file and tears down the connection to the file
what is a high-level language?
close to human language, like in Python compiler can work through your code line-by-line
what are the requirements for concatenation and repetition?
concatenation requires two strings repetition requires a string and an integer
what is a file stream?
contains a buffer of the information from the file, and provides information to the program connects the file information on disk to the program
what does the 'try' suite do?
contains code that we want to monitor for errors during its execution if an error occurs anywhere in the suite, Python looks for a handler that can deal with the error, otherwise the program halts and error message is shown
what is a cache?
copy of information from the file that is stored
what is a buffer?
data area shared by hardware devices or program processes that operate at different speeds or with different sets of priorities allows each device or process to operate without being held up by the other
what does the diamond shape in a flowchart represent?
decision
what is a data type?
defines a collection of data values and a set of predefined operations on those values
what are the aspects of an algorithm?
detailed effective specific behavior general purpose
how is a string mapped?
each character is associated with an integer, such as UTF-8. function ord( ) takes a character and returns its UTF-8 integer value then the function chr( ) takes an integer and returns the UTF-8 character
what are the strategies for program design/problem solving?
engage/commit visualize/see try it/experiment simplify analyze/think relax
what does accessing a file mean?
establishing a connection between the file and the program and moving data between the two
what is computer software?
executable programs: word processor, spread sheet, internet browser, etc
all the elements in a list should be of the same data type?
false
what is pseudocode?
false code used to describe how a computer or an algorithm works acts as an intermittent step before developing actual code
what is the CPU cycle?
fetch instruction decode instruction execute operation store result repeat
example of an exception?
indexing past the value of a list, value not found, file not closed, etc
what is a overflow error?
indicates an arithmetic operation has exceeded the limits of the current python runtime typically due to excessive float values
what is a zerodivision error?
indicates the second argument used in a division or modulus operation was zero
what are the components of a computer system
input devices- mouse, keyboard, joystick, microphone output devices- monitor, printer central processing unit- brain of the computer main memory- RAM (volatile and temporary) secondary storage of memory (nonvolatile and permanent)- hard drives, floppy disc, USB network- bluetooth, wifi
what does a parallelogram represent in a flowchart?
input/output
what is 'a' mode?
file's contents are left intact and new data is appended at file's end creates and opens a new file if file doesn't exist
what is 'a+'?
file's contents are left intact and read/write at file's end creates and opens a new file if one doesn't exist
what is a text file?
files where control characters such as "/n" are translated; generally human readable
what is a run-time error?
happens when Python understands what you're saying, but is unable to follow your instructions
what is a key error?
happens whenever a dict() object is requested and the key is not in the dictionary
what is a relational expression?
has two operands and one relational operator operator- compares the value of its two operands
what is selection?
how programs make choices, and it is the process of making choices that provides a lot of the power of computing
what are the defaults of slicing?
if either start or finish are not provided, it defaults to the beginning of the sequence for start and the end of the sequence for finish step size is 1
what is an import error?
raised when you try to import a module that doesn't exist may happen if you make a mistake typing in a name
what are the aspects of a program?
readability robustness/reliability correctness
what is 'r+' mode?
reads and overwrites from the file's beginning gives an error if file doesn't exist
what does the line represent in a flowchart?
relationship between shapes
what does pop( ) do?
removes the element whose index is specified by default removes the last item
what does sort( ) do?
sorts the elements of same data type can be ascending or descending order
what does an oval represent in a flowchart?
start/end
what is an iterative statement?
statement that causes a statement or collection of statements to be execute zero, one, or more times
what does the 'len' function do?
takes an argument as a string and returns an integer length of the string len(my_str) = some integer
what is "end of line" character?
terminates each line of text in a text file /n by default
what are the two types of files?
text files and binary files
what is a value error?
there's a problem with the content of the object you tried to assign value to
are strings immutable or mutable?
they're immutable so you can't change them once you make them they can be used to make another new string though
what is half open range for slicing mean?
this means that the first index is included in the sequence and the last index is one after what is included
Lists are mutable, i.e. they can be changed
true
in a Boolean expression, any value except 0, " ", [ ], is considered"
true
how do you check the type of value you're using?
type(my_str)
what is an indentation error?
unexpected incident; need to have correct indentation
what is an input function?
used to take data from the person using your code that is then used throughout the program
how many bits are in one byte?
8 bits in one byte
how do you print a new line?
'\n'
how do you print a tab?
'\t'
What is a file?
a collection of data that is stored on secondary storage like a disk or a thumb drive
what is the difference between a compiler and an interpreter?
a compiler converts the entire program at one time and then executes in bulk an interpreter goes line by line
what is the syntax of slicing?
[start : finish : step] where start is the index of where we start the subsequence and finish is the index of one after where we end the subsequence
what is an 'except' suite?
it's activated if an error that occurs in the 'try' suite matches the type of exception
what does the "join" method do?
joins all the elements in consecutive indexes of a list into one string
what are the operations that can be performed on a list?
length concatenate repeat
what kind of operators are 'and', 'or', and 'not'?
logical operators
what is a compiler?
looks at each python instruction, one at a time, and turns that instruction into something that can be run
what makes a string invalid?
mixing up quotation types
what is a syntax error?
most basic type of error arise when the python parser is unable to understand a line of code almost always fatal
how do you copy a string?
my_str = 'hi mom' new_str = my_str[ : ]
how do you reverse a string?
my_str = 'hi mom' reverse_str = my_str[ : : -1]
what is the 'r' mode?
opens a file in read-only mode, initial position at the beginning of the file will give error message if file doesn't exist
what is computer hardware?
physical devices: processor, memory, keyboard, monitor, mouse, etc
what do triple quotes do?
preserves both the vertical and horizontal formatting of the string; allows you to type tables, paragraphs, etc and preserve the formatting
what does a rectangle represent in a flowchart?
process
what is an index error?
raised when you refer a sequence which is out of range try to call the fourth index when there's only three items
what determines true vs false for strings?
uses mapping and the assigned integers to each character, if a character has a higher assignment it's the larger element compare elements of strings if they're equal, moves to the next character in each if they're unequal, the relationship between those to characters are the relationship between the string if one ends up being shorter, but equal, the shorter is smaller
what is a type error?
when two unrelated types of objects are combined
what are keywords?
words or phrases in python that carry out a predetermined purpose