startswith() and endswith()

What you'll learn

Topic	Focus
startswith()	Check the beginning
endswith()	Check the ending
Case sensitivity	Upper ≠ lower
Real validation	Files, URLs & emails

Visual roadmap

These methods only check a string—they never modify it.

Easy memory: Start = Left · End = Right

1. startswith() → Check the beginning

Returns True if the string begins with the given text.

s = "Python is an oop lang"

print(s.startswith("Python"))   # True
print(s.startswith("Pyt"))      # True
print(s.startswith("lang"))     # False

Why does "Pyt" work? Because it matches the prefix, not the entire word.

Check	Result
"Python"	True
"Pyt"	True
"Py"	True
"lang"	False

2. Case sensitivity

Python compares characters exactly.

s = "Python is an oop lang"

print(s.startswith("Python"))   # True
print(s.startswith("python"))   # False

Case-insensitive solution:

s = "Python is an oop lang"

print(s.lower().startswith("python"))
# True

Convert both sides to the same case when case does not matter.

3. endswith() → Check the ending

Returns True if the string finishes with the given text.

s = "Python is an oop lang"

print(s.endswith("lang"))   # True
print(s.endswith("ng"))     # True
print(s.endswith("g"))      # True
print(s.endswith("la"))     # False

Suffix matching:

Check	Result
"lang"	True
"ng"	True
"g"	True
"la"	False

4. startswith() vs endswith()

They inspect opposite sides of the string.

Method	Looks at	Returns
startswith()	Beginning	True / False
endswith()	Ending	True / False

5. Real-world applications

These methods are commonly used for validation.

name.endswith(".py")

url.startswith("https://")

email.endswith("@gmail.com")

line.startswith("#")

Playground

Copy and run this example.

s = "Python is an oop lang"

print("startswith Python:", s.startswith("Python"))
print("startswith python:", s.startswith("python"))

print("endswith lang:", s.endswith("lang"))
print("endswith ng:", s.endswith("ng"))

Expected output:

startswith Python: True
startswith python: False

endswith lang: True
endswith ng: True

Use the lesson playground at the bottom of the page to run this code live.

Quick knowledge check

1. Is "Python is an oop lang".startswith("python") True?
   Answer: No — it is case-sensitive.

2. Does "hello.txt".endswith(".txt") return True?
   Answer: Yes.

3. Do these methods modify the string?
   Answer: No — they only return True or False.

30-second visual revision

Method	Easy memory
startswith()	Check the beginning
endswith()	Check the ending
Return type	Boolean (True / False)
Case	"Python" ≠ "python"

Interview shortcut: Start → startswith() · End → endswith() · Both are Boolean checks and never change the string.

Next: String handling practice programs.