1 Python_Data_Structures_Basics.ipynb

Kernel: Python 3 (ipykernel)

Python Basics: Lists, Strings, Tuples, and Dictionaries

This notebook provides a simple explanation and quick practice for Python's core data structures.

1. Lists

Lists are mutable collections used to store multiple items in a single variable. []

• it can have multiple datatypes

a=["abc",12.4,-2,"b"]
a
len(a)
## access the member
a[1]
a[-1]

# Creating a list
fruits = ["apple", "banana", "cherry"]
fruits

# Adding an item
fruits.append("orange")
print("After append:", fruits)

fruits.insert(2,"grapes")

fruits

# Removing an item
fruits.remove("banana")
print("After removal:", fruits)

del fruits[2]

Common List Methods

• append(item) – Add item to end

• insert(index, item) – Insert at a position

• remove(item) – Remove first occurrence

• pop(index) – Remove item at index

• sort() – Sort list

• reverse() – Reverse list

Quick Practice:

• Create a list of your 3 favorite movies.

• Add one more movie.

• Remove the second movie.

• Print the final list.

2. Strings

Strings are sequences of characters enclosed in quotes. They are immutable.

# Working with strings
text = "Hello, Python!"
print(text)
print("Uppercase:", text.upper())
print("Lowercase:", text.lower())
print("First 5 chars:", text[:5])

del text[4]

len(text)

text.append("folks")

Quick Practice:

• Create a string with your name.

• Print it in uppercase and lowercase.

• Slice and print the first 4 characters.

Common String Methods

• upper() – Convert to uppercase

• lower() – Convert to lowercase

• strip() – Remove surrounding whitespace

• replace(old, new) – Replace substrings

• find(sub) – Return index of substring

3. Tuples

Tuples are immutable sequences, often used to store related items.

d=()
d=("a",2,3,)
#del d[0]
d
d[0]

# Creating a tuple
person = ("Alice", 30, "Engineer")
print(person)
print("Name:", person[0])

Quick Practice:

• Create a tuple with your name, age, and city.

• Print each element using indexing.

4. Dictionaries

Dictionaries are collections of key-value pairs.

Tuple Characteristics and Functions

• Immutable: Cannot be changed after creation

• Can contain mixed data types

• Supports indexing and slicing

• Functions: len(), count(), index()

d={}
d["A"]=12
d["B"]=14
d
d["A"]
del d["A"]
d

# Creating and accessing a dictionary
student = {"name": "Bob", "age": 21, "course": "Data Science"}
print(student)
print("Name:", student["name"])

# Adding a new key-value pair
student["grade"] = "A"
print("Updated student:", student)

d["B"]=19
d["c"] = (6,7)
d.keys()
d.values()
d.items()
d.pop("c")

Quick Practice:

• Create a dictionary for a car with keys: brand, model, year.

• Print the model.

• Add a new key: color and assign a value.

Common Dictionary Methods

• get(key) – Return value for key

• keys() – Return all keys

• values() – Return all values

• items() – Return key-value pairs

• update(dict) – Update with another dict

• pop(key) – Remove key and return value

5. Loops in Python

Python supports two main types of loops: for and while. They are used to execute a block of code repeatedly.

For Loop Example

Loop through a list and print each item:

n="piyush"
d=[1,2,3]

for i in range(1,6):
    print(i)

for i in range (0,12,2):
    print(i)

for i in range (8,2,-1):
    print(i)

for i in (n):
    int(input()) 

colors = ["red", "green", "blue"]
for color in colors:
    print(f"Color: {color}")

### Input number of elements
n = int(input("Enter number of elements in the list: "))

# Initialize empty list
my_list = []

# Loop to input elements
for i in range(0,n):
    element = input(f"Enter element {i+1}: ")
    my_list.append(element)

print("List:", my_list)

While Loop Example

num = 0
while num <= 5:
    print("Number:", num)
    num = num+1

Number: 0
Number: 1
Number: 2
Number: 3
Number: 4
Number: 5

Questions:

• Create a user input list to dipaly even number between givem range

• Create a user input dictionary for Name as key and Age as Value

d={}
d[1]="A"
d[2]="B"
d

{1: 'A', 2: 'B'}

# Input number of key-value pairs
n = int(input("Enter number of key-value pairs in the dictionary: "))

# Initialize empty dictionary
emp = {}

# Loop to input keys and values
for i in range(n):
    empID = input(f"Enter ID {i+1}: ")
    Name = input(f"Enter value for '{empID}': ")
    emp[empID] = Name

print("Dictionary:", emp)

Enter number of key-value pairs in the dictionary: 3
Enter ID 1: 1
Enter value for '1': Abha
Enter ID 2: 2
Enter value for '2': Ashi
Enter ID 3: 4
Enter value for '4': kia
Dictionary: {'1': 'Abha', '2': 'Ashi', '4': 'kia'}