python data_error ai_generated true

KeyError: 'missing_key'

ID: python/keyerror-key-not-found-in-dict

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2025-03-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8 active — — —
3.9 active — — —
3.10 active — — —

Root Cause

A test tries to access a key in a dictionary that does not exist.

generic

中文

测试尝试访问字典中不存在的键。

Workarounds

  1. 95% success Use dict.get() with a default value 
    value = my_dict.get('missing_key', 'default')
  2. 90% success Check key existence before access 
    if 'missing_key' in my_dict: value = my_dict['missing_key']

Dead Ends

Common approaches that don't work:

  1. Using dict.get() without default 50% fail

    Returns None, which may cause subsequent errors if None is not handled.

  2. Catching KeyError silently 70% fail

    Silent catch hides the missing key and may lead to incorrect test results.