String Handling in Python

A string is text — anything wrapped in quotes. You can use single or double quotes, and Python gives you many tools to slice, search, and transform text:

name = "Asha"
city = 'Jalgaon'

# f-strings let you drop variables right into text
print(f"{name} lives in {city}")   # Asha lives in Jalgaon

# Strings can be joined with +
greeting = "Hello, " + name
print(greeting)                    # Hello, Asha

Let's cover the parts you'll use every day.

Indexing and slicing

A string is a sequence of characters, each with a position starting at 0. You can grab one character or a slice:

text = "Python"

print(text[0])      # P   (first character)
print(text[-1])     # n   (last character)
print(text[0:3])    # Pyt (characters 0, 1, 2 — stops before 3)
print(text[2:])     # thon (from index 2 to the end)
print(text[:4])     # Pyth (from start up to index 4)
print(text[::-1])   # nohtyP (reversed!)

Slicing [start:stop] includes the start index but stops before the stop index — the same rule as range().

f-strings: the modern way to format

f-strings (formatted string literals) are the cleanest way to build text with variables. Put an f before the quotes and write {expression} inside:

name = "Ravi"
score = 87.5

print(f"{name} scored {score}%")              # Ravi scored 87.5%
print(f"Half of the score is {score / 2}")    # Half of the score is 43.75

# You can format numbers too: round to 1 decimal place
print(f"Score: {score:.1f}")                  # Score: 87.5

Useful string methods

Strings come with dozens of built-in methods. Here are the ones beginners use most:

text = "  Hello, World  "

print(text.strip())          # "Hello, World"  (removes outer spaces)
print(text.upper())          # "  HELLO, WORLD  "
print(text.lower())          # "  hello, world  "
print(text.replace("World", "Python"))  # "  Hello, Python  "

sentence = "one two three"
print(sentence.split())      # ['one', 'two', 'three']  (splits on spaces)

words = ["a", "b", "c"]
print("-".join(words))       # "a-b-c"  (joins a list into a string)

print("Hello".startswith("He"))   # True
print("apple".find("p"))           # 1  (position of first 'p')
print(len("Python"))               # 6  (length of the string)

Strings are immutable

You cannot change a single character of a string in place — strings are immutable, like tuples. Methods like .replace() return a new string instead:

text = "cat"
# text[0] = "b"          # ERROR: strings can't be changed in place

new_text = text.replace("c", "b")   # make a new string
print(new_text)          # bat
print(text)              # cat — the original is unchanged

A practical example

# Clean up and format a user's full name

raw = "   ASHA  patil  "

# strip outer spaces, fix the casing
cleaned = raw.strip().title()    # .title() capitalises each word
print(f"Welcome, {cleaned}!")    # Welcome, Asha  Patil!

# Count words
word_count = len(cleaned.split())
print(f"Words in name: {word_count}")

Common mistakes

• Trying to change a string in place: text[0] = "x" raises a TypeError. Build a new string with a method like .replace().
• Forgetting .strip() on user input: Stray spaces from input() cause comparisons like text == "yes" to fail. Clean input with .strip() first.
• Mixing quote types wrongly: "He said "hi"" breaks. Use single quotes inside double quotes, or escape with \".
• Using + to join a number: "Age: " + 25 raises a TypeError. Use an f-string or str(25).
• Confusing .find() and .index(): .find() returns -1 if the substring is missing; .index() raises an error. Pick based on whether you want a crash or a sentinel.

FAQ

What's the difference between single and double quotes? None functionally. Use whichever avoids escaping — double quotes around text that contains an apostrophe, for instance.

How do I write a multi-line string? Wrap it in triple quotes: """line one\nline two""". Everything between the triple quotes, including line breaks, becomes part of the string.

Are f-strings the best way to format? For most cases, yes — they're readable and fast. They've been available since Python 3.6 and are the modern standard.

---

Strings build on what you learned about Variables & Data Types in Python. For transforming many strings at once, see List Comprehensions in Python. More topics on the Python learning hub.

Want to learn this properly? Join the waitlist for our Python course — taught in Jalgaon, beginner-friendly.