Python NameError

When you run Python code, you may get a NameError such as the following:

NameError: name 'x' is not defined

The x in the error will vary depending on your program.

The error means that Python looks for something named x but finds nothing defined by that name.

Common causes

Common causes include:

• you misspelled a variable name
• you got the casing of a variable wrong; Python is case-sensitive
• you forgot to put quotes around a string, so Python thinks it's a variable
• you misspelled a function name, such as pring instead of print
• you used a variable without first having assigned a value to it
• you started using a variable before its definition
• you are trying to use a variable whose definition is only valid in a different scope
  • for example, a variable defined inside a function cannot be accessed outside of it
• you called a function before its definition was reached

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