Python Overall

Question 1

What is a Value in Python?

Answer 1

A value is one of the basic things a program works with. A value can be a letter or a number. Examples of values are 1, 2, and ‘Hello, World!’

Question 2

What are examples of Value Types?

Answer 2

2 is an integer, and ‘Hello, World!’ is a string, so-called because it contains a “string” of letters.

Question 3

How can we identify strings? because they are enclosed in quotation marks.

Answer 3

You can identify strings because they are enclosed in quotation marks. Python gives us the freedom to use either single or double quotes, so the string ‘Hello, World’ and “Hello, World!” are the same string. Note, however, that we must begin and end every string with the same type of quotation mark.

Question 4

(True or False) Commas act as separators in Python.

Answer 4

True

Question 5

What does a Print Statement allow us to do?

Answer 5

The print statement allows us to display both strings and integers when we run the created program.

Question 6

(True or False) If you are not sure of your Value Type, the Python Interpreter can tell you the values when you run your program.

Answer 6

True

Question 7

What is the type code for String?

Answer 7

str

Question 8

What is the type code for Integers?

Answer 8

int

Question 9

In Python, numbers with a decimal point belong to a type called?

Answer 9

float

Question 10

What is a Float?

Answer 10

Numbers with a decimal point belong to a type called float because these numbers are represented in a format called floating-point.

Question 11

How do you identify types in Python?

Answer 11

By calling the type function into your statement - E.g. print(type(“Hello World!”)) This will define the type for you.

Question 12

(True or False) When using underscores in large numbers underscores are included.

Answer 12

False

Question 13

(True or False) A variable is a name that refers to a value.

Answer 13

True

Question 14

What can be used for Variable names?

Answer 14

They can contain letters, numbers, and underscores. However, they cannot start with a number. Although it is legal to use uppercase letters, it is customary to use all lower-case letters in variables names.

Question 15

(True or False) The underscore character _ can appear in a name.

Answer 15

True. It is often used in names with multiple words, such as my_name, etc. Variable names can start with an underscore character, but we generally avoid doing this unless we are writing library code for others to use.

Question 16

What is a Syntax error?

Answer 16

Python can only execute a program if the syntax is correct; otherwise, the interpreter displays an error message. Syntax refers to the structure of a program and the rules about that structure. For example, parentheses have to come in matching pairs, so (1 + 2) is legal, but 8) is a syntax error. If there is a single syntax error anywhere in your program, Python will display an error message and quit, and you will not be able to run your program.

Question 17

What is a Runtime error?

Answer 17

This error does not appear until after the program has started running. These errors are also called exceptions because they usually indicate that something exceptional (and bad) has happened.

Question 18

What is a Semantic error?

Answer 18

If there is a semantic error in your program, it will run successfully in the sense that the computer will not generate any error messages, but it will not do the right thing. It will do something else. Specifically, it will do what you told it to do.
The problem is that the program you wrote is not the program you wanted to write. The meaning of the program (its semantics) is wrong. Identifying semantic errors can be tricky because it requires you to work backward by looking at the output of the program and trying to figure out what it is doing.

Question 19

Explain the Python String identifier() Method.

Answer 19

A string is considered a valid identifier if it only contains alphanumeric letters (a-z) and (0-9), or underscores (_). A valid identifier cannot start with a number, or contain any spaces.

Question 20

Python has a number of other keywords or reserved words. Explain.

Answer 20

The keywords or reserve words are used to define the syntax and structure of the Python language. In Python, keywords are case-sensitive. There are 33 keywords in Python 3.7. This number can vary slightly over the course of time.

Question 21

Python reserves 31 keywords for its use:

Answer 21

This is the list(however it may vary):
and - del - from - as - elif - global - assert - else - if - break - except - import - class - exec - in - continue - finally - is - def - for - lambda not - while - or - with - pass - yield - print - raise - return - try

Question 22

Explain the function of Keywords in Python.

Answer 22

Keywords are the reserved words in Python. We cannot use a keyword as a variable name, function name, or any other identifier. They are used to define the syntax and structure of the Python language.

Question 23

In Python, what is the interpreter, and how does it works?

Answer 23

An interpreter is a kind of program that executes other programs. When you write Python programs, it converts source code written by the developer into an intermediate language which is again translated into the native language/machine language that is executed.

Question 24

In Python, what is a Statement?

Answer 24

A statement is a unit of code that the Python interpreter can execute. A Python program contains a sequence of statements. If there is more than one statement, the results appear one at a time as the statements execute.

Question 25

Give an example of two kinds of Statements in Python.

Answer 25

Print and Assignment

Question 26

Programmers go through a process when creating a program. What does it look like?

Answer 26

1. They design the algorithm. They document the steps that the program needs to perform to work correctly. This is done in English and we normally call this pseudo-code.
2. They code the pseudo-code in a programming language. In our case that will be Python.
3. They execute, or run, the program looking for defects. This is called testing.
4. Each time that they discover a defect they analyze the issue and fix it. Then they go back to step 3 and continue testing it until they are confident that the defects have been fixed.

Question 27

What is a program?

Answer 27

A program is a sequence of instructions that specifies how to perform a computation. The computation might be something mathematical, such as solving a system of equations or finding the roots of a polynomial, but it can also be a symbolic computation, such as searching and replacing text in a document or (strangely enough) compiling a program.

Question 28

Name 5 basic instructions that appear in just about every language:

Answer 28

Input: Get data from the keyboard, a file, or some other device.

Output: Display data on the screen or send data to a file or other device.

Math: Perform basic mathematical operations like addition and multiplication.

Conditional execution: Check for certain conditions and execute the appropriate code.

Repetition: Perform some action repeatedly, usually with some variation.

Question 29

What is debugging?

Answer 29

Programming is error-prone. For whimsical reasons, programming errors are called bugs and the process of tracking them down is called debugging.

Question 30

What are Operators and Operands?

Answer 30

Operators are special symbols that represent computations like addition and multiplication. The values the operator is applied to are called operands.

The operators +, -, *, /, and ** perform addition, subtraction, multiplication, division, and exponentiation, as in the following examples:

20 + 32
year - 1
price * tax_rate
90 / 60
5 ** 2

Question 31

(Complete the statement) To see the values generated by the mathematical formulas, we must…

Answer 31

We must be sure to first assign values to the variables and then use the print function to display them.

Question 32

What is an Expression?

Answer 32

An expression is a combination of values, variables, and operators. A value all by itself is considered an expression, and so is a variable, so the following are all legal expressions - (assuming that the variable x has been assigned a value):
17
x
x + 17

Question 33

Explain Operator Precedence and Associativity.

Answer 33

When more than one operator appears in an expression, the order of evaluation depends on the rules of precedence. For mathematical operators, Python follows mathematical convention.

Question 34

What does the acronym PEMDAS stand for?

Answer 34

• Parentheses have the highest precedence and can be used to force an expression to evaluate in the order you want. Since expressions in parentheses are evaluated first, 2 * (3 - 1) is 4, and (1 + 1) ** (5 - 2) is 8. You can also use parentheses to make an expression easier to read, as in (minute * 100) / 60, even if it doesn’t change the result.
• Exponentiation has the next highest precedence, so 2 ** 1 + 1 is 3, not 4, and 3 * 1 ** 3 is 3, not 27.
• Multiplication and Division have the same precedence, which is higher than Addition and Subtraction, which also have the same precedence. So, 2 * 3 - 1 is 5, not 4, and 6 + 4 / 2 is 8, not 5.
• With the exception of exponentiation, operators with the same precedence are associated from left to right. So, the expression 5 - 3 - 1 is 1, not 3, because the 5 - 3 happens first and then 1 is subtracted from 2.

Question 35

Explain Integer Division and Modulus Operators.

Answer 35

Python also has a second division operator that is used to perform integer division, which is the division that truncates the result. The symbol for this operator is // rather than just /.

Question 36

What is an Integer?

Answer 36

An integer is a whole number (not a fractional number) that can be positive, negative, or zero. Examples of integers are: -5, 1, 5, 8, 97, and 3,043. The integers are generated from the set of counting numbers 1, 2, 3, . . . and the operation of subtraction. When a counting number is subtracted from itself, the result is zero.

Question 37

There is one additional operator that is often used in conjunction with the // operator, which is %. Explain.

Answer 37

Although the symbol is the percent symbol, this operation does not involve taking a percentage but instead gives the remainder after performing integer division. It is referred to as the modulus or remainder operator.

Question 38

What is truncated in math?

Answer 38

Truncating is a method of approximating a decimal number by dropping all decimal places past a certain point without rounding. Example: 3.14159265 can be truncated to 3.1415.

Question 39

What is the meaning of concatenation?

Answer 39

The concatenation of two or more numbers is the number formed by concatenating their numerals. … For example, the concatenation of 1, 234, and 5678 is 12345678. The value of the result depends on the numeric base, which is typically understood from the context.

Question 40

Explain how the + operator works with strings.

Answer 40

The + operator works with strings, but it is not addition in the mathematical sense. Instead, it performs concatenation, which means joining the strings by linking them end to end. The type of operands will determine whether that operator performs addition or concatenation.

Question 41

What is User Input? (Soft of set up as a two-way communication designed to collect information or exchanges from the user or (target audience). A script or series of questions that prompts a reply from the user or (target audience).

Answer 41

Python user input from the keyboard can be read using the input() built-in function. The input from the user is read as a string and can be assigned to a variable. After entering the value from the keyboard, we have to press the “Enter” button. Then the input() function reads the value entered by the user. The program resumes, based on established input returns, after assessing what the user typed as a string.

Question 42

What is the symbol or Escape Character for Next Line?

Answer 42

The character sequence \n represents a newline, which is a special character that causes a line break.

Question 43

In Python, what is a Glyph?

Answer 43

A glyph is a vectorized graphical shape or marker that is used to represent your data. A few categories of Glyph are shapes like circles, diamonds, squares, and triangles. Character sequences that begin with \ are often also referred to as escape characters. They can be used to represent characters that do not have an associated glyph.

Question 44

What is Eval?

Answer 44

The Eval is a built-in- function used in python, eval function parses the expression argument and evaluates it as a python expression. In simple words, the eval function evaluates the “String” like a python expression and returns the result as an integer.

Question 45

How can you add Comments to Python?

Answer 45

As programs get bigger and more complicated, they get more difficult to read. Formal languages are dense, and it is often difficult to look at a piece of code and figure out what it is doing, or why.

For this reason, it is a good idea to add notes to your programs to explain in natural language what the program is doing.

These notes are called comments, and in Python, they start with the # symbol.

When the # symbol is the first symbol on the line, the whole line is a comment.

You can also put comments at the end of the line after other Python code.

Everything from the # to the end of the line is ignored—it has no effect on the program.

There is no evidence of the comments in the output.

Question 46

What is the best way to use Comments?

Answer 46

Comments are most useful when they document non-obvious features of the code. It is reasonable to assume that the reader can figure out what the code does; it is much more useful to explain why.

Good variable names can reduce the need for comments, but names that are too long can make complex expressions hard to read, so there is a trade-off.

Question 47

What is Pseudocode?

Answer 47

It is a technique for designing the control structure of programs. Pseudocode combines English with important keywords of Python.
Pseudocode will consist primarily of a high-level English description of the required actions. When we translate our pseudocode into Python, we will retain the pseudocode as comments.

Question 48

Explain Python Assignment Statements.

Answer 48

Python assignment statements assign objects to names. The target of an assignment statement is written on the left side of the equal sign (=), and the object on the right can be an arbitrary expression that computes an object. Assignment creates object references instead of copying the objects.

Question 49

Explain the Python print() Function

Answer 49

The print() function prints the specified message to the screen or other standard output device. The message can be a string or any other object, the object will be converted into a string before written to the screen.

Question 50

What is a Boolean Expression?

Answer 50

A Boolean expression is an expression that is either true or false.
The following examples use the operator ==, which compares two operands and produces True if they are equal and False otherwise.
So 5 == 5 would evaluate to True, whereas 5 == 6 would evaluate to False.

Like arithmetic expressions, Boolean expressions can be assigned to variables:

different = 5 == 6

Question 51

(True or False)True and False are special values that belong to the type bool; they are not string.

Answer 51

True.

Question 52

Comparison Operators

The == operator is one of six comparison operators for comparing values; the others are:

Answer 52

x == y    #x is equal to y 
x != y     #x is not equal to y
x > y      #x is greater than y
x < y      #x is less than y
x >= y     #x is greater than or equal to y
x <= y     #x is less than or equal to y

Question 53

Order of Operations of Logical Operators

Answer 53

not #higest precedence
and # middle precedence
or #lowest precedence