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input(): reading text from the user

How input() reads a line from the user in Python: the prompt, why the result is always a str, converting it with int() and float(), the ValueError on bad input, and EOFError.

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print() writes to the screen. input() does the other direction: it shows an optional prompt, waits for the user to type a line and press Enter, and returns what was typed. It’s the simplest way to make a script interactive.

Every example here was run with Python 3.13. The behavior was checked against the official input() docs.

The basic call

name = input("What is your name? ")
print(f"Hello, {name}!")

The text in the parentheses is the prompt. It’s written to the screen without a newline, so the cursor waits right after it. The docs say the line is read, “converts it to a string (stripping a trailing newline)”, and returned.

If you type Ada, the screen shows:

What is your name? Ada
Hello, Ada!

The Ada after the prompt is what you typed. It’s not printed by the program.

The result is always a str

Even when the user types digits, input() returns text:

age = input("How old are you? ")
print(type(age))

If you type 36, this prints:

<class 'str'>

So age + 1 would raise a TypeError. Convert the text first:

age = input("How old are you? ")
years = int(age) + 1
print(f"Next year: {years}")

For decimals use float(). The conversion functions are covered in the type conversion post.

Spaces are kept

input() removes only the trailing newline. Spaces stay:

print(repr(input("Anything: ")))

If you type spaced and press Enter, the output is:

'  spaced  '

repr() shows the quotes and the spaces, so you can see them. To remove spaces at both ends, use strip(), the string method from the strings post.

Common mistake: bad input

The user can type anything, so if they type thirty, int(age) stops the program with the ValueError from the type conversion post. Check the input before you convert it, or handle the error with try and except (exceptions post). A quick check with a string method is often enough:

text = input("How old? ")
print(text.isdigit())

If you type 36, this prints True. isdigit() only accepts digits, so -5 and 3.5 return False.

When there is no input

When the input stream ends, input() raises an error instead of returning an empty string. You see it when a script runs with no terminal attached, such as in a pipeline or from a file:

name = input("What is your name? ")

EOFError: EOF when reading a line

The docs say: “When EOF is read, EOFError is raised.” An empty line (just pressing Enter) is different: that returns "", and the program keeps running.

Common mistakes

  • Forgetting the space in the prompt. input("Name?") puts the cursor right after the question mark. Add a space at the end of the prompt if you want a gap.

What’s next

Next: the date type, for days on a calendar.

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