Computer Programming Lab - Exam 1

Variables & types , conditionals, booleans, functions, loops, & data structures (strings, lists, dictionaries, & tuples)

String (str)

Can be letters, words, sentences, or numbers enclosed in quotes.

Ex:

message = ‘Hello, world!’

Integer (int)

A data type that can be any whole number but not decimals.

Ex:

fav_number = 9

Float

A decimal

Ex:

month = 10.0

Boolean (bool)

A variable that can either be True or False.

Ex:

will_ace_exam = True

Local Variable

A variable defined inside functions.

Global Variable

A variable defined outside functions and can be “seen”/used by any function.

List

A sequence of values.

Can be ints, floats, strings, bools, & other lists.

Lists are mutable.

Uses square brackets - [ ]

Ex:

numbers = [1, 2, 3]

Dictionary (dict)

Has key-value pairs - key : value.

Can be ints, floats, strings, & a value can be a list.

Dictionaries are mutable.

Uses curly brackets { }

Ex:

songs = {‘LOONA’ : ‘High High’, ‘DREAMCATCHER’ : ‘Jazz Bar’}

Tuple

Tuples are immutable lists. Need to create a new tuple to “edit” it.

Uses parentheses ( )

Ex:

greetings = (‘hello’, ‘hola’, ‘bonjur’)

Loops

Used to repeat something over and over again.

While Loop

Repeats until a condition is no longer True and becomes False.

Has uncertainty.

Ex:

while CONDITION:
BODY

For Loop

Repeats a condition in a pre-defined group of items.

Need to create a new variable (name is related to the singular item).

Ex:

for ELEMENT in GROUP:
BODY

Break

Used to stop a loop from continuing/leave the loop early.

Continue

Ignores the rest of the BODY for the current element. Then, skips to the next element in the body.

Range

Gives a sequence of numbers.

Starts from 0 and increments by default.

Ex:

range(3) = [0, 1, 2]
range(start, end, increment) - range(1, 7, 2) = [1, 3, 5]

range(start, end, decrement) - range(3, 0, -1) = [3, 2, 1]

Length (len)

A built-in function that returns the number of characters in a string.

Ex:
fruit = ‘banana’
len(fruit)
6

Slice

Returns a segment of a string.

Can be the front, back half, everything, or empty.

Starts at index 0 and excludes the last character.

[:9], [9:], [ ], [9:9]

Ex:
[starting letter # : ending letter #]
fruit[:3]
‘ban’

Append

Adds new element to the end of a list.

Ex:
list.append(element)

Sort

Sorts a list alphabetically or from low to high.

Ex:
list.sort() - works only w/ lists - doesn’t modify original list
sorted() - works w/ anything - makes a new list

String Concatenation +

Joins strings without adding a space in between.

String Concatenation ,

Combines strings and automatically adds a space in between.

If Statement

Evaluates a condition (True or False) and executes the specified block of code if the condition is True.

Ex:
if CONDITION:
BODY

If/Else Statement

Evaluates a condition (True or False) and executes the 1st block of code if the condition is True, if not then it executes the 2nd block.

Ex:
if CONDITION:
BODY 1
else:
BODY 2

Else If Statement (elif)

Used to check multiple conditions sequentially.

Ex:
if condition_1:
elif condition_2: - checks if condition_1 is False AND condition_2 is True
else:

Define (def)

Used to start a function definition.

Ex:
def function_name:

return result

def function_name(parameters):

return result