"Nameerror: Name '' Is Not Defined" After User Input in Python

Python get input from user - error name not defined

Use raw_input() instead, since you're using Python 2.7.

raw_input gets the input as text (i.e. the characters that are typed), but it makes no attempt to translate them to anything else; i.e. it always returns a string.

input gets the input value as text, but then attempts to automatically convert the value into a sensible data type; so if the user types ‘1’ then Python 2 input will return the integer 1, and if the user types ‘2.3’ then Python 2 input will return a floating point number approximately equal to 2.3

input is generally considered unsafe; it is always far better for the developer to make decisions about how the data is interpreted/converted, rather than have some magic happen which the developer has zero control over.

It is the reason why that automatic conversion has been dropped in Python 3 - essentially; - raw_input in Python 2 has been renamed to input in Python 3; and there is no equivalent to the Python 2 input magic type conversion functionality.

NameError: name '' is not defined after user input in Python

Do not use input() in 2.x. Use raw_input() instead. Always.

Why do I get a NameError when using input()?

You are using Python 2 for which the input() function tries to evaluate the expression entered. Because you enter a string, Python treats it as a name and tries to evaluate it. If there is no variable defined with that name you will get a NameError exception.

To fix the problem, in Python 2, you can use raw_input(). This returns the string entered by the user and does not attempt to evaluate it.

Note that if you were using Python 3, input() behaves the same as raw_input() does in Python 2.

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