Strings

A string stores textual data. Defined using single or double quotes.

integer_var = 100
string_var = "sample text"

Output Formatting

employee = 'Bob'
job_title = 'Developer'
office = 'Innovation Hub, Floor 3'

print('-------------------')
print(f"Name: {employee}")
print(f"Position: {job_title}")
print(f"Location: {office}")
print('-------------------')

User Input Handling

Input values are stored as strings by default.

username = input('Enter login ID: ')
print(f"Login ID: {username}")

access_key = input('Enter security key: ')
print(f"Security key: {access_key}")

Indexing and Slicing

Acces characters via zero-based indices.

data_string = "algorithm"
print(data_string[0])  # 'a'
print(data_string[4])  # 'o'

# Substring extraction
print(data_string[0:4])  # 'algo'
print(data_string[3:])   # 'orithm'
print(data_string[::-1])  # 'mhtirogla'

Common String Methods

sample = "data processing example"

# Search operations
print(sample.find('proc'))      # 5
print(sample.count('a'))         # 3

# Transformation
print(sample.upper())          # 'DATA PROCESSING EXAMPLE'
print(sample.replace('a', '@')) # 'd@t@ process@ng ex@mple'

# Validation
print(sample.isalpha())         # False
print('123'.isdigit())           # True

Lists

Ordered mutable collections supporting mixed data types.

team_members = ['Anna', 'Ben', 'Clara']
mixed_data = [42, 'text', 3.14]

Iteration Tehcniques

For loop:

for member in team_members:
    print(member)

While loop:

index = 0
while index < len(team_members):
    print(team_members[index])
    index += 1

List Modification

Append: Add single element

team_members.append('David')

Extend: Merge collections

additional = ['Eva', 'Frank']
team_members.extend(additional)

Insert: Position-specific addition

team_members.insert(1, 'Xander')

Modify: Update by index

team_members[2] = 'Carlos'

Remove:

del team_members[3]        # By index
team_members.pop()          # Last element
team_members.remove('Ben')  # By value

Sorting:

numbers = [5, 2, 8, 1]
numbers.sort()              # Ascending
numbers.sort(reverse=True)  # Descending
numbers.reverse()           # In-place reversal

Nested Lists

departments = [
    ['HR', 'Finance'],
    ['Engineering', 'QA'],
    ['Marketing', 'Sales']
]

Tuples

Immutable ordered sequences defined with parentheses.

coordinates = (40.7128, -74.0060)
mixed_tuple = ('A', 100, 2.5)

Access Patterns

print(coordinates[0])      # 40.7128
print(mixed_tuple[1:])     # (100, 2.5)

Built-in Methods

test_tuple = ('a', 'b', 'c', 'a')
print(test_tuple.count('a'))  # 2
print(test_tuple.index('c'))  # 2

Dictionaries

Key-value pair collections with unique keys.

employee_record = {
    'id': 789,
    'name': 'Sarah',
    'department': 'Research'
}

Value Access

print(employee_record['name'])  # 'Sarah'
print(employee_record.get('title', 'N/A'))  # Default handling

Dictionary Operations

Update:

employee_record['id'] = 790

Add new entry:

employee_record['status'] = 'Active'

Delete:

del employee_record['department']
employee_record.clear()  # Empty contents

Dictionary Analysis

print(len(employee_record))          # Key count
print(list(employee_record.keys()))   # All keys
print(list(employee_record.values())) # All values

Common Operations

Operators

# Concatenation
print([1, 2] + [3, 4])        # [1, 2, 3, 4]
print('Hi' * 3)               # 'HiHiHi'

# Membership test
print('a' in ('a', 'b'))      # True

Built-in Functions

# Length calculation
print(len({'x': 1, 'y': 2}))  # 2

# Extremes identification
print(max([5, 8, 2]))         # 8

# Element deletion
temp_list = [10, 20, 30]
del temp_list[1]

Mutability Characteristics

Mutable types: Lists, dictionaries (modifiable in-place) Immutable types: Strings, numbers, tuples (create new instances when changed)