# UnboundLocalError: cannot access local variable 'x' where it is not associated with a value

**Code:** `UnboundLocalError` · **Category:** Python · **Seen on:** Python

A function assigns to a variable somewhere, which makes it local everywhere in that function — so reading it before the assignment fails.

## Meaning

Python decides scope at compile time. If a function contains x = ..., every x in that function is local, even before the assignment. Modifying a module-level counter inside a function is the classic case.

## Common causes

- Incrementing a global inside a function (count += 1)
- Variable assigned only in one branch
- Assigned in try but used in except/finally

## Quick fix

1. Pass values in and return results instead of using globals
2. Use global/nonlocal deliberately
3. Initialise before branches

## Detailed fix by platform

### Python

1. 

```python
def increment():
    global counter
    counter += 1
```


## How to diagnose

1. **Assignment** — Where is it assigned in the function?
2. **Read** — Is it read before that?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/python/unboundlocalerror)