S364 Midterm
To be executed, what does Python programming language use?
Interpreter
floating point
a type that represents numbers with fractional parts
argument
a value provided to a function when the function is called. This value is assigned to the corresponding parameter in the function.
Will the following code cause an error: Print("Hello world!")
True
When executing the following code, what error would be raised? x =4 x + "USA"
TypeError, because x is an integer and "USA" is a string. The data types are different
return value
the result of a function passed back to the caller
What happens when you run the following 3 codes? 1) int(True) 2)int(False) 3) int(None)
1) 1 2) 0 3) TypeError
What do you get from the following code? 10/5
2.0
What will x be after the code is executed: x = 43 x = 43 + 1
44
list
a mutable data structure with a sequence of elements
statement
a section of code that represents a command or action. So far, the statements we have seen are assignments and print expression statements.
assignment
a statement that assigns a value to a variable
What operator in Python joins strings together? For example "Hello" (operator) "World"
+
What are true between lists and tuples
- Processing tuples is faster than processing lists - lists use brackets ([]) as the boundaries of the items and tuples use parentheses as the boundaries of the items
How can you execute code in Jupyter notebook?
- Shift+Enter - Ctrl+Enter - From the menu Cell -> Run Cells
What situations are a good candidate to be handled in a try/except structure?
- Try to open a file with user provided file path but the file path is incorrect - A number expected from a user input but the user enters letters such as A, B, C
What statements are correct in describing the control flow of a try/except structure?
- When the code executes without any exception, the code block inside try is executed and code inside except is skipped and program continues - When the code execution encounters an exception, the code block inside try after the line of code that encounters the error is skipped, code inside except is executed and programs continues.
When would you use a markdown cell?
- add a title to a Jupyter notebook - add headings to sections of a jupyter notebook
What is true about and if statement?
- an if statement must have a condition - if statement is used to implement conditional flow - the code blocks in the branches must be indented (an if statement does not need to be matched with an else branch)
What are the advantages of using jupyter notebook?
- communicate and share results - code development - documentation
What are the reasons to use comments in code?
- describe or explain logic - provide information such as author, version, date of code - hide some code from the interpreter so they won't be executed
To access the first three characters in a string that's stored in a variable named message, you can use this code:
- first_three = message[:3] - first_three = message[0:3]
For sequential access of a file, what is true?
- once a piece of data is read, it cannot be read again - read the file from beginning to end, cannot skip ahead
What can variable names not include in python?
-, numbers, spaces
What is the result of 10 % 3?
1
void function
A function that doesn't return a value.
dictionary
A mapping from a set of keys to their corresponding values.
parameter
A name used inside a function to refer to the value which was passed to it as an argument.
function
A named sequence of statements that performs some useful operation. Functions may or may not take parameters and may or may not produce a result
function definition
A statement that creates a new function, specifying its name, parameters, and the statements it executes.
function call
A statement that executes a function. It consists of the function name followed by an argument list.
import statment
a statement that reads a module file and makes the module functions available
Given list1 = ["H", "e", "l", "l", "o"] what does "&".join(list1) do?
Return a string: "H&e&l&l&o"
dot notation
The syntax for calling a function in another module by specifying the module name followed by a dot (period) and the function name.
Python code is always executed from top to the bottom without any exceptions
True
set
a collection of unordered items with unique values
tuple
a immutable data structure with a sequence of elements
What is true of the following code? x = "4" x = float(x)
after the execution, x now contains 4.0
key
an object that appears in a dictionary as the first part of a key-value pair
value
an object that appears in a dictionary as the second part of a key-value pair
modulus operator
an operator, denoted with a percent sign (%), that works on integers and yields the remainder when one number is divided by another
conditonal
at the decision point, the code could go through different branches that are mutually exclusive
DateTime
contains complete date and time information
date
contains the date information including year, month, day, etc. (doesn't include time)
time
contains the time information including hour, minute, or second
TimeDelta
contains time interval or duration information. The difference between two dates or times
What word indicates that start of a function?
def
how to remove a key and its value
dictionary.pop('key') del dictionary['value']
loop
execute certain code repeatedly for a multiple number of times
Sequential
execute the code line by line in the order written (this is the default execution)
What data type does the value 5.3 have?
float
If you accidentally deleted a cell and wanted to get it back, what can you do?
in the (command) mode, use the keyboard shortcut "z"
which of the following is correct about python? - it is a high-level language - it is a machine language - it is a low-level language - it is an assembly language
it is a high level language
To determine the length of a string that's in a variable named city, you can use this code:
len(city)
Where in the computer is a variable such as "x" stored after the following Python line finishes? X = 123
main memory
function
pre-defined code module executed when needed
exception handling
purposefully designed code executed when unexpected problems occur in normal execution
What type of code will get you a set of all the values found in both set1 and set2?
set1 | set2 set1.union(set2)
What code will get you a set of all the values in set1 but not in set2 and in set2 but not in set 1? (values that are not in both sets)
set1.symmetric_difference(set2)
What is the function of the secondary memory in a computer?
store information for the long term, even beyond a power cycle
When open a file to write to it, we need to pass an argument to the mode parameter, what value should we pass to mode?
w