As a beginner developer, you often come across codes like this in conditional statements:

if value:
    print("Value exists!")

At first, it can be confusing to understand what the simple if value: statement is checking.
Especially the two below:

  • None
  • "" (empty string)

Both of these are evaluated as False, which makes them feel similar.

But is that really the case?

Falsy Values

In Python, the following values are evaluated as False in conditional statements:

  • None
  • False
  • 0, 0.0
  • "" (empty string)
  • [] (empty list)
  • {} (empty dictionary)
  • set(), () and other empty collections

Therefore, if not value: captures all of these at once.

None and "" Are Different

These two look different and behave differently.

value1 = None
value2 = ""

print(value1 == value2)  # False
print(value1 is value2)  # False

print(bool(value1))  # False
print(bool(value2))  # False
  • == checks value equality while is checks identity.
  • None is a special object that means “there is no value yet”,
  • whereas "" is a string that is empty.

Empty vs None speech bubble comparison

In the image above, the man on the left holds a speech bubble but says nothing — this corresponds to the empty string "".
The woman on the right has no speech bubble at all — this corresponds to None.

Both of these are evaluated as False under the following condition:

male_voice = ""
female_voice = None

if not male_voice and not female_voice:
    print("Both say nothing!")  # Executes as both are False

So how do we distinguish in practice?

For instance, let’s look at handling user input:

username = user_input.get("username", None)
  1. If the user didn’t input anything → None
  2. If the user input an empty string → ""

If you want to handle these differently?

if username is None:
    print("No input at all!")
elif username == "":
    print("You entered an empty string.")
else:
    print("Entered value:", username)

Common Mistakes in Practice

The following code sometimes unintentionally filters out all Falsy values:

if not username:
    print("No input provided")

However, this condition includes not only empty strings but also None, 0, empty lists, etc.
Thus, intentions need to be made clear:

  • Even if empty, a string should be allowed → if username is None:
  • A string should exist but can be empty → if username != "":
  • There should be no value at all → if not username:

In Conclusion

None and "" are not the same. However, both behave like False.
Understanding this difference will allow your code to be more clear and free of bugs.

In the next post, I will delve deeper into other Falsy values like 0, [], {} and explore the differences between is and ==!