TypeError: 'NoneType' object is not subscriptable

What you see

def find_user(users, name):
    for user in users:
        if user["name"] == name:
            return user

users = [{"name": "ada", "email": "ada@example.com"}]
user = find_user(users, "grace")
print(user["email"])

Traceback (most recent call last):
  File "/home/me/project/main.py", line 8, in <module>
    print(user["email"])
          ~~~~^^^^^^^^^
TypeError: 'NoneType' object is not subscriptable

What it means

You used square brackets, as in user["email"] or rows[0], on a value that is None. None holds no items, so there is nothing to look up. "Subscriptable" means "supports []".

The line in the traceback is where the None was used, not where it came from. Read upwards to the last place the variable was assigned. In the example, find_user finds no "grace", falls off the end of the loop and returns None.

Why it happens

• A function that does not always return. A function that reaches its end without return returns None, as find_user does when no name matches.
• Keeping the result of an in-place method. items = items.sort(), items = items.append(x) and random.shuffle(items) all return None. The list changed, and you replaced it with None.
• A lookup that found nothing. dict.get(), re.match(), os.environ.get() and many library calls return None when there is no match.
• A variable set to None up front and only filled in on some paths.

How to fix it

Decide what should happen when there is nothing, and check for it before indexing:

user = find_user(users, "grace")
if user is None:
    print("no such user")
else:
    print(user["email"])

If the method changes the list in place, call it on its own line, or use the version that returns a new list:

items.sort()            # changes items, returns None
items = sorted(items)   # returns a new, sorted list

When the None should never happen, say so at the source: raise LookupError(f"no user {name!r}") at the end of find_user gives a clearer error than the one you got.

How each Python version words it

Run on CPython 3.9.6, 3.10.22, 3.11.17, 3.12.15, 3.13.17, 3.14.9 and 3.15.1, on October 25, 2026.

The wording is the same on every version in the table. Python 3.11 and later also underline the expression that failed, which tells you which of several subscripts on one line was None.