Why Does Python Throw a \'NameError: name is not defined\' Error?

Python's NameError: Definite Debugging

Encountering the "NameError: name is not defined" error in Python can be frustrating, hindering your code's execution. Let's investigate the causes behind this error and find an effective solution.

The error arises when Python encounters a reference to an unknown variable or class. In the provided code:

<code class="python">s = Something()
s.out()

class Something:
    def out():
        print("it works")</code>

The interpreter attempts to access the Something class after the s variable has been defined. However, in Python, class definitions must be made before their usage; otherwise, the interpreter cannot recognize them.

To rectify the situation, redefine the Something class before utilizing it:

<code class="python">class Something:
    def out(self):
        print("it works")

s = Something()
s.out()</code>

Another commonality in this error involves instance method definition. Instance methods require self as their first argument, representing the instance itself. Ensure that you include self when defining instance methods:

<code class="python">class Something:
    def out(self):
        print("it works")</code>

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