Strings in Python
Python strings "immutable" hain — ek baar bana lene ke baad, unke individual characters ko modify nahi kar sakte (s[0] = 'X' error dega). Koi bhi "modification" actually ek naya string return karti hai.
f-strings (f"...") Python ka modern, powerful string-formatting tareeka hai — variables ko seedha {} ke andar embed kar sakte ho, printf()-style format specifiers ki zaroorat nahi.
name = "Aarav"
# name[0] = 'B' # ERROR: strings immutable hain
greeting = "Hello, " + name # naya string banta hai
print(greeting) # "Hello, Aarav"
age = 20
message = f"{name} is {age} years old" # f-string — bahut clean
print(message)
print(name.upper()) # "AARAV"
print(name.lower()) # "aarav"
print(len(name)) # 5- Strings immutable hain — modify nahi hoti, naya string banta hai
- f-strings (f"...") = modern, readable string formatting
- .upper()/.lower()/len() jaise bahut saare built-in methods
split() string ko list mein todता hai (delimiter se), join() list ko string mein jodता hai, strip() extra whitespace hataता hai — ye teeno bahut common real-world text-processing operations hain.
sentence = " Hello World Python "
print(sentence.strip()) # "Hello World Python" (extra spaces gaye)
words = sentence.strip().split(" ") # ["Hello", "World", "Python"]
print(words)
joined = "-".join(words) # "Hello-World-Python"
print(joined)Python mein 3 tareeke hain string format karne ke: purana % (C-style, avoid karo), .format() (thoda purana lekin abhi bhi use hota hai), aur f-strings (modern, sabse readable aur fast — hamesha ise prefer karo).
name, age = "Aarav", 20
# Purana % style (avoid):
print("%s is %d" % (name, age))
# .format() style:
print("{} is {}".format(name, age))
# f-strings (modern, PREFERRED):
print(f"{name} is {age}")