Python Data Types, Lists & For Loop

1. Data Types

  A data type specifies what kind of value a variable holds.

• Numeric Types

age = 25          # int
price = 99.99     # float
number = 2 + 3j   # complex	

• String Type

name = "John"     # str

• Boolean Type

is_student = True   # bool

• Collection Types

fruits = ["Apple", "Banana", "Mango"]     # list
colors = ("Red", "Green", "Blue")         # tuple
numbers = {1, 2, 3}                       # set
student = {"name": "John", "age": 20}     # dict

• Special Type

value = None

• Check Data Type

x = 100
type(x)

Output

int

2. Lists

 A list is an ordered, mutable collection that can store multiple values.

• Create a List

fruits = ["Apple", "Banana", "Mango"]
print(fruits)

• Access Elements

print(fruits[0])   # Apple
print(fruits[1])   # Banana
print(fruits[-1])  # Mango

• Change an Item

fruits[1] = "Orange"
print(fruits)

• Add Items

fruits.append("Grapes")
print(fruits)

• Insert Item

fruits.insert(1, "Kiwi")

• Remove Item

fruits.remove("Apple")

• Length of List

print(len(fruits))

• List Slicing

numbers = [10, 20, 30, 40, 50]
print(numbers[1:4])

Output

[20, 30, 40]

3. For Loop

 A for loop is used to iterate over a sequence such as a list, string, tuple, or range.

• Loop Through a List

fruits = ["Apple", "Banana", "Mango"]

for fruit in fruits:
   print(fruit)

• Using range()

for i in range(5): 
	print(i)

Output

0
1
2
3
4

• Start and End

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

• Loop Through a String

for letter in "Python":
   print(letter)

Output:

 P
 y
 t
 h
 o
 n    

• Loop with Index

fruits = ["Apple", "Banana", "Mango"]
for index, fruit in enumerate(fruits):
   print(index, fruit)

Output

0 Apple
1 Banana
2 Mango