How to check if the string is empty?

python

empty-string

whitespace

truthiness

byAlex Kataev·Aug 15, 2024

Working with strings in Python? Here's how to check if a string is empty:

if not my_string:
    print("Empty")
else:
    print("Not empty")

Just substitute my_string with your string. This built-in falsy behavior of empty strings in Python has you covered!

Emptiness and the invisible intruder: whitespaces

Now, not every empty looking string is innocent. You've got the invisible guests: whitespaces. Luckily, it's easy to spot these intruders.

if not my_string.strip():
    print("Empty...or full of invisible intruders")
else:
    print("Contains visible characters")

By using str.strip(), you can banish these lurking whitespaces from both ends of your string.

What would Python do? Embracing Pythonic style

Like a Zen master asking, "What's the sound of one hand clapping?" a Pythonista asks, "What's the way of checking an empty string?"

# Python, show me the way
empty_string = ""

if empty_string:  # Should I?
    print("Wise guy, aren't ya?")
else:  # So Zen
    print("That's the Python way!")

Getting explicit: double-checking with an empty string

When in doubt, spell it out! Explicit comparisons leave no room for misunderstanding.

if my_string == "":  # I'm watching you 👀
    print("Empty, we double-checked")

This literally checks if my_string is an equal to an empty string. Explicit and clear.

Truth or dare: understanding truthiness

In Python, truth extends beyond True and False; nearly everything has a truthiness value.

A string that's full of characters? It's True.
An empty string? It's False.

This built-in feature has truth value testing to thank for.

Whitespace detectives: using isspace()

Let's put on our detective hats 🕵️‍♀️. If a string is full of whitespace but no characters, it's still 'empty'.

# Detective work on strings
just_whitespace = "   "

if not just_whitespace or just_whitespace.isspace():  # Check-mate!
    print("You can't fool me, whitespace!")
else:
    print("We've got other characters here!")

Crafting checks with custom functions

Looking to customize your string checks? Try creating a function for it!

# Function that sees through strings
def see_through(s):
    return bool(s and not s.isspace())  # Clever, aren't we?

# Putting our function to use
if see_through(my_string):
    print("Aha! Got ya!")
else:
    print("Just empty space here...")

Smoke test: checking against various inputs

Always test your code against different inputs for that confidence boost!

test_strings = ["", " ", "Real words", "\n", "\t", None]

for test_str in test_strings:
    if not test_str or test_str.isspace():  # Let's see what you're made of
        print(f"Testing: '{test_str}' ")