What is UnboundLocalError and reason for it

Introduction

In this blog, we would discuss What is UnboundLocalError and the reason for it. If you’ve ever seen the error message “UnboundLocalError: local variable ‘x’ referenced before assignment”, you know that it can be frustrating to try to figure out what’s going on. This error occurs when you try to use a variable that hasn’t been assigned a value yet. There are a few ways that this error can occur. One common way is if you try to return a variable before assigning it a value.

Examples for Causes of Error and solutions

Let us consider an example

def my_func():
  print(x) 
  x = 10 
  
my_func()

This will cause an error because the print statement is trying to use the x variable before it has been assigned a value. To fix this error, you need to make sure that all of the variables that you’re using in a function are assigned a value before you try to use them. In the first example, you can fix the error by moving the return statement after the x

The reason for UnboundLocalError is when you try to use a variable before it has been assigned a value. For example, let’s say you have a function that tries to print a variable:

def print_var():
  print(z)
  z="hello"


print_var()

If you try to call this function without first assigning a value to the x variable, you’ll get an UnboundLocalError. The reason this error occurs is when you try to use a variable before it has been assigned a value. Python assumes that you’re trying to create a local variable. However, if you don’t actually assign a value to the variable, it can’t be created, which is why you get the error. To fix this error, you need to make sure that you assign a value before you try to use it.

 For example, say you have a function that increments a local variable

def increment():
  x += 1 
  return x

increment()

If you try to call this function without first assigning a value to x, you’ll get an UnboundLocalError

The reason this error occurs is that when you try to increment x, Python interprets x as a local variable, even though it hasn’t been assigned a value yet. So when it tries to increment the local variable x, it can’t find it because it doesn’t exist yet. To fix this error, you need to make sure that x has been assigned a value before you try to increment it.

Also, read – What is a Floating point error and how to solve it?