Chapter 2 notes 2

Question 1

Print function is what

Answer 1

A string-a sequence of characters enclosed in a single quotes (‘)
Text here is not preceded by
Out[1]
It also does not display quotes in strings
You can also enclose them with (“) but Python programmers generally prefer single quotes

Question 2

Printing a comma-separated list of items

Answer 2

The print function can receive a comma-separated list of arguments as in:
In[3]: print(‘Welcome’, ‘to’, ‘Python!’)
Out[3] Welcome to Python!

Question 3

What is an escape character?

Answer 3

When a backlash () appears in a string. The backlash and character immediately follow it and form an escape sequence. Ex: \n represents the newline character escape sequence which tells print to move the output cursor to the next line

In[4]: print(‘Welcome\nto\n\nPython!]
Out[4]: Welcome
To

Python!

Question 4

What is a continuation character and what symbol does it use?

Answer 4

You use a continuation character to split a long string (or a long statement) over several lines by using the \ continuation character, as the last character or line to ignore the line break:
In[5]: print(‘this is a longer string, so we \
…: split it over two lines’)
Out[5]: this is a long string, so we split it over two lines

Question 5

Calculations can be performed in print statements, provide example

Answer 5

In[6]: print(‘Sum is’, 7 + 3)
Out[6]: Sum is 10

Question 6

The ________ function instructs the computer to display information on the screen

Answer 6

Print

Question 7

Values of the ________ data type contain a sequence of characters

Answer 7

String (type str)

Question 8

Write a Python expression that displays the type of ‘word’

Answer 8

In[1]: Type(‘word’)
Out[1]: str

Question 9

What does the following print statement display?
In[2]: print (‘int(5.2)’, ‘truncates 5.2 to’, int (5.2))

Answer 9

In[2]: print (‘int(5.2)’, ‘truncates 5.2 to’, int (5.2))
Out[2]: int(5.2) truncates 5.2 to 5

Question 10

Triple-quoted strings

Answer 10

Begin and end with three double quotes (“ “ “) or three single quotes (‘ ‘ ‘) The style guide for Python code recommends three double quotes

Question 11

What are the triple-quoted strings used to create?

Answer 11

Multiple strings
Strings containing single or double quotes
Docstrings, which are the recommended way to document the purposes of certain program components

Question 12

When including quotes in strings, use double-quote characters and not single quotes, ex

Answer 12

In[1]: print(‘Display “hi” in quotes’)
Out[1]: Display “hi” in quotes

Not single quotes, view picture
Unless you use the \’ escape sequence:
In[2]: print(‘Display \’hi\’ in quotes’)
Out[2]: Display ‘hi’ in quotes

Question 13

What is a syntax error?

Answer 13

A violation of Python’s language rules. In IPython, it will display information about the line of code that caused the syntax error and points to the error with a ^ symbol.
It also displays the message
SyntaxError: invalid syntax

Question 14

How to avoid using \’ and \” inside strings?

Answer 14

Enclose such strings in triple quotes. Ex:
In[4]: print (“””Display ‘hi’ and ‘bye’ in quotes”””)
Out[4]: Display ‘hi’ and ‘bye’ in quotes

Question 15

Explain the steps of the snippet that executed an input function for the a given name

Answer 15

In[1]: name = input (“What is your name?”)
Out[1]: What’s your name? ______

In[2]: name
Out[2]: Rebeca

In[3]: print(name)
Out[3]: Rebeca

Here the input displays its string argument-called a prompt-to tell the user what to type and wait for the user to respond. We typed Rebeca (without quotes) and pressed Enter
The function input then returns (gives back) those characters as a string that the program can use. We assigned that storing to a variable name

Question 16

String concatenation

Answer 16

In[7]: value1 = input (‘Enter first number: ‘)
Out[7]: Enter first number: 7

In[8]: value2 = input (‘Enter second number: ‘)
Out[8]: Enter second number: 3

In[9]: value1 + value2
Out[9]: ‘73’

Rather than adding the integers, Python “adds” the string values ‘7’ and ‘3’, producing the string ‘73’
It creates a new string containing the left operand’s value followed by the right operand’s value

Question 17

Getting an integer from the user
If you need an integer, convert the string to an integer using the built-in int function
Ex

Answer 17

In[10]: value = input (‘Enter an integer: ‘)
Out[10]: Enter an integer __7__

In[11]: value = int(value)

In[12]: value
Out[12]: 7

Question 18

How to combine the int function into snippets

Answer 18

Do this instead, but if the other one was performed then change the name to another_value
In[13]: value = int (input(‘Enter another integer: ‘))
Out[13]: Enter another integer: 13

In[14]: value
Out[14]: 13

Question 19

Using the integer function is good for change values into ______

Answer 19

Integers
This is good when you want to add them up instead of getting ‘73’, you can get an actual answer of ‘10’ like in the previous numerical examples

Question 20

What happens when a string cannot be converted to an integer?

Answer 20

A ValueError message occurs

Question 21

T/F The function int also can convert a floating-point value to an integer

Answer 21

True
In[17]: int(10.5)
Out[17]: 10

Question 22

How to convert strings into floating-point numbers?

Answer 22

Uses the built in float function
In[18]: float (‘6.2) * 3.3
Out[18]: 20.46

Question 23

The built-in __________ function converts a floating-point value to an integer value or converts a string representation of an integer to an integer value

Answer 23

Int

Question 24

T/F Built-in function get_input requests and obtains input from the user

Answer 24

False. The built-in function’s name is input

Question 25

What is a Boolean expression?

Answer 25

A condition with the value True or False

Question 26

Give 2 examples of a true/false Boolean expression from the book

Answer 26

In[1]: 7 > 4
Out[1]: True

In[2]: 7 < 4
Out[2]: False

Question 27

What are Python keywords?

Answer 27

Words like True or False, language that Python reserves for these features. Using keywords as an identifier causes a SyntaxError
True and False are each capitalized

Question 28

What is the meaning for these conditions?
1. X > y
2. X < y
3. X >= y

Answer 28

1. X is greater than y
2. X is less than y
3. X is greater than or equal to y

Question 29

What is the meaning for these conditions?
1. X <= y
2. X == y
3. X != y

Answer 29

1. X is less than or equal to y
2. X is equal to y
3. X is not equal to yW

Question 30

What happens when there are spaces between its pair of symbols?
Ex:
In[3]: 7 > = 4

Answer 30

Syntax error occurs, this also occurs if you reverse the symbol in the operators by writing != as =! Instead