Debug 4.3. Total Points

Explore

Debug 4.3. Total Points

Debug 4.3. Total Points

Code Clips

Display to screen (Python console)

basic display

print('Add text here') # with a new line

print('Add text here', end=' ') # stay on the same line, set end to space character

print('\n\n') # display blank line (2)

Key Points about using print()

place message in round brackets ( )

place text in straight 'single quote marks ' (not curly ones) (double quote also OK)

display message with variables and text

print(number + ' + ' + str(number) + ' = ' + answer)

Display variables together in a message by concatenating text and variables.

Notice the spaces inside ' text '

The + concatentation operator is exactly the same symbol as the addition operator

When using concatenation, python requires you to cast non-string values/variables to a string value by using the str() function

If you want to be sure that numbers are added arithmetically then put them in brackets: print(player + str(i+1)) and not print(player + str(i) + str(1))

python offers another way to display multiple items: use commas

automatic conversion to string values, automatic space inserted

please note that this is not concatenation

print ('The score is', score, 'and the type is', type(score))

Variables

you do not need to declare variables in python

when you assign a (new) values to a variable, it takes on the type of that value

(python is a dynamically typed-language)

variable names should be descriptive and always used with exactly the same spelling and case

str - a string stores text, any combination of (letters, digits and symbols)

textVar = '' # assign a (empty) string value

int - stores positive or negative Integers (whole numbers)

intVar = 0 # assign an integer value

float - stores decimal numbers

floatVar = 0.0 # assign a real number/ decimal number/ floating point

There is no chracter type in python, simply use a string of length 1

char - stores single characters which can be letters, digits or symbols.

characterVar = 'F' # assign a single character string

bool - the values True or False

booleanVar = True # use a capital T or F

checking the type of a variable

you can check the type of a variable by using the type() function

score = 50

print('The score is ' + str(score) + ' and the type is ' + str(type(score)))

>> The score is 50 and the type is <class 'int'>

Keyboard Input, Storing With Variables

All input is read as text/string.

You should cast input values to the required data-type before storing into a variable

python will not warn you if you enter the wrong type of value until later if you try to use it for an operation

String - stores text; any combination of (letters, digits and symbols)

textVar = input('Insert prompt here: ')

Integer - stores positive or negative whole numbers

intVar = int(input('Insert prompt here: '))

float - stores decimal numbers

floatVar = float(input('Insert prompt here: '))

Character - stores single characters which can be letters, digits or symbols

this is exactly the same as for string/text

charVar = input('Insert prompt here: ')

Boolean - stores true or false

you must enter the values 1 for True and 0 for False for this to work

booleanVar = bool(int(input('Insert prompt here: ')))

Text operation

Concatenation of text

join text in username variable to the literal text, store as eMailAddress.

The + concatentation operator is exactly the same symbol as the addition operator

When using concatenation, python requires you to cast non-string values/variables to a string value by using the str() function

If you want to be sure that numbers are added arithmetically then put them in brackets: print(player + str(i+1)) and not print(player + str(i) + str(1))

emailAddress = username + '@gmail.com'

Arthimetic Operators

Addition

This code adds two numbers together and assigns the result to the additionAnswer variable

additionAnswer = numberOne + numberTwo

keeping a count by adding on 1

If you had to count how many keys are on your keyboard you might check along the rows thinking: 1, 2, 3, … It’s a very common task where you add on 1 to your count. In fact you a re following a well known algorithm:

start count at 0

add 1 to count to update it

add 1 to count to update it again ..

add 1 to count (keep going up to the last key on the keyboard)

display count

in Python you can add on 1 to a count variable like this

count = 0

count = count + 1

print('The final count is ' + str(count))

Subtraction

This code subtracts numberTwo from numberOne and assigns the result to the subtractionAnswer variable.

subtractionAnswer = numberOne - numberTwo

Divsion real number division

This code divides numberOne by numberTwo and assigns the result to the divisionAnswer variable.

The type of answer is float

divisionAnswer = numberOne / numberTwo

Divsion integer division

This code divides numberOne by numberTwo and assigns the result to the divisionAnswer variable.

The type of answer depends on numberOne and numerTwo

If they are both integers int then the answer will be an integer so 9/2 will be 4 (remainder 1 is thrown away)

If one or both numbers are decimal (double) then the answer will be a double (9.0/2 is 2.5, 9/2.0 is 4.5, 9.0/2.0 is 4.5)

divisionAnswer = numberOne // numberTwo

Multiplication

This code multiplies two numbers and assigns the result to the multiplicationAnswer variable.

multiplicationAnswer = numberOne * numberTwo

Conditional constructs and comparison operators

take care to position the start and end of IF…THEN and IF…ELSE constructs in the correct place

make sure that the code you want to be nested inside does indeed appear between the start and the end.

the nest is created by indenting 2 spaces from the left-hand margin

it is a good idea to reformat the program code after adding in a new construct, use replit auto format feature.

IF…THEN Construct

see below for examples of expression with comparison-operator

code nested inside the construct is carried out when the conditional expression is True

otherwise all the nested code is ignored

if expression_with_comparison-operator :

# one or more conditional statements

# end if

IF…ELSE construct

see below for examples of expression with comparison-operator

when the conditional expression is True then code nested inside the first part of the construct is carried out, code in the second part is ignored

otherwise the code nested in the bottom part is carried out and code in the first part is ignored

if expression_with_comparison-operator :

# one or more conditional statements

else :

# one or more conditional statements

# end if

Comparison Operators

the comparison operators are used in the head of the IF..THEN and IF..ELSE constructs

basic format is LHS comparison-operator RHS

One of or both LHS and RHS can be variables

The value in the variable(s) will cause the conditional expression to be either true or to be false

Equal to comparison operator

if variableName == 7 :

Not Equal to comparison operator

if variableName != 7 :

Greater Than comparison operator

if variableName > 7 :

Less Than comparison operator

if variableName < 7 :

Less Than or Equal to comparison operator

no more than 7, 7 or below

if variableName <= 7 :

Greater Than or Equal to comparison operator

at least 7, 7 or more

if variableName >= 7 :

Fixed Loop construct

take care to position the start and end of a loop constructs in the correct place

make sure that the code you want to be nested inside does indeed appear between the start and the end.

the nest is created by indenting 2 spaces from the left-hand margin

it is a good idea to reformat the program code after adding in a new construct, use replit auto format feature.

for i in range(0, stopNumber, 1) :

# one or more statements to be repeated

# nested inside the loop

# end loop

often you may want the user to enter a number to set the number of loop cycles needed

# prompt for how many times the loop has to repeat

cycles = int(input('How many loop cycles are needed? '))

# use the variable as the stopNumber for the loop

for i in range(0, cycles, 1) :

# one or more statements to be repeated

# nested inside the loop

# end loop

using the value of the loop variable to count up on each cycle

to display a count from 0, display i

to display a count from 1, display (i+1)

for i in range(0, cycles, 1) :

# display the loop variable from 0, display a count from 1

print('The value of i is: ' + str(i))

print('This is cycle number: ' + str((i + 1)))

# end loop

Arrays

An array in python can can be implemented as a list to store multiple values in a single variable. List elements in python can store values of different types.

Declare array, display array element

Array of Strings

# sets up an array of strings with list of values

textArray = ['text A', 'text B', 'text C']

# prints out first element in array

print(textArray[0])

# prints out second element in array

print(textArray[1])

Array of Integers

# sets up an array of integers with list of values

intArray = [1, 23, 456, 789]

# prints out first element in array

print(intArray[0])

# prints out second element in array

print(intArray[1])

Array of floats

# sets up an array of floats with list of values

floatArray = [0.1, 2.3, 4.56, 78.9]

# prints out first element in array

print(intArray[0])

# prints out second element in array

print(intArray[1])

Array without values

To set up an array of any type before assigning values to array elements

# sets up an array of 5 elements for any type

arrayName = [None] * 5

# find out how many items in the list to be stored

numberOfItems = int(input('Enter number of values you want to store: '))

# set up array and set the size to match the number of items

arrayName = [None] * numberOfItems

working with an array

use a variable as an array index

# sets up an array of strings with list of values

textArray = ['text A', 'text B', 'text C']

# set a indexA to 1 and display value stored in the element

indexA = 1;

print('Second element is ' + str(textArray[indexA]))

# set a indexB to user input and display value stored in the element

indexB = int(input('Choose an element to display 0-2: '))

print('Your chosen element is ' + str(textArray[indexB]))

calculate size of an array

sometimes it is useful to store the length of an array

# sets up an array of strings with list of values

textArray = ['text A', 'text B', 'text C']

arraySize = len(textArray)

print('The array has ' + str(arraySize) + ' elements.')

Looping Through an Array (traversing)

this code uses nameOfArray.length directly in the loop avoiding the need for an additional size variable

# sets up an array of strings with list of values

textArray = ['text A', 'text B', 'text C']

# prints out each element of array

for i in range(0, len(textArray), 1) :

print(textArray[i])

# end loop

Screen effects

Pauses Program

This line of code pauses the program for 3 seconds. 5, would delay for 5 seconds. For visual effect.

You must have import time at the start of the program

Ask your teacher/tutor for help with this if it does not work.

time.sleep(3);

Clear Screen

This line of code clears the screen. (This will only work in replit)

print('\033[H\033[2J')

Display to screen (Python console)

basic display

display message with variables and text

Variables

Keyboard Input, Storing With Variables

Text operation

Arthimetic Operators

Conditional constructs and comparison operators

Declare array, display array element

working with an array

Screen effects

Gallery

Want to print your doc?
This is not the way.

Try clicking the ⋯ next to your doc name or using a keyboard shortcut (

CtrlP

) instead.