Chapter 8: Strings in Python

Chapter 8: Strings in Python

String ka matlab hota hai characters ka sequence. Ab sikhenge string methods, slicing, formatting aur manipulation.

1. String Creation

Single ya double quotes se string banate hain.

name = "Ravi"
message = 'Hello World'

2. String Indexing & Slicing

String ke characters ko access karne ke liye index ka use hota hai. Index 0 se start hota hai.

text = "Python"
print(text[0]) # Output: P
print(text[-1]) # Output: n
print(text[1:4]) # Output: yth
P
n
yth

3. String Methods

  • lower(): Sab lowercase mein convert karta hai
  • upper(): Sab uppercase mein convert karta hai
  • strip(): Extra spaces hatata hai
  • replace(): Word ko replace karta hai
  • split(): String ko list mein todta hai
txt = " Hello Python "
print(txt.lower())
print(txt.strip())
print(txt.replace("Python", "World"))
print(txt.split())
" hello python "
"Hello Python"
" Hello World "
['Hello', 'Python']

4. String Concatenation

Do ya zyada strings ko jodna concatenate kehlata hai.

a = "Hello"
b = "World"
print(a + " " + b)
Hello World

5. String Formatting

Python 3 mein modern formatting f-strings ke through hoti hai.

name = "Ravi"
age = 21
print(f"My name is {name} and I am {age} years old.")
My name is Ravi and I am 21 years old.

6. Common String Mistakes

text = "Hello
print(text) # ❌ String not closed
text = "Hello"
print(text) # ✅

7. Check String

Use in to check if substring exists:

msg = "Welcome to Python"
print("Python" in msg) # True
print("Java" not in msg) # True

8. Multiline Strings

Use triple quotes for multi-line:

para = """
This is line 1.
This is line 2.
"""
print(para)
This is line 1.
This is line 2.

9. Looping Through a String

Har character ko access karne ke liye for loop ka use hota hai.

for char in "Python":
 print(char)
P
y
t
h
o
n