Explain LEGB scoping in Python.

Summary

LEGB is Python's name lookup order: Local, Enclosing, Global, then Built-in scope.

Longer Answer

When Python resolves a name, it first checks the current function or comprehension local scope, then enclosing function scopes for closures, then the module global scope, and finally builtins. Assignment normally creates a local name unless global or nonlocal is declared.

Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions.

Key Points

• When Python resolves a name, it first checks the current function or comprehension local scope, then enclosing function scopes for closures, then the module global scope, and finally builtins
• Assignment normally creates a local name unless global or nonlocal is declared
• Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions
• For 'Explain LEGB scoping in Python.', a strong interview answer should define the mechanism, name the common failure mode, and explain the production decision it affects.

Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions

Comparison / Tradeoffs

Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions. |

Summary

LEGB is Python's name lookup order: Local, Enclosing, Global, then Built-in scope.

Longer Answer

For 'Explain LEGB scoping in Python.', a strong interview answer should define the mechanism, name the common failure mode, and explain the production decision it affects.

Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions.

Key Points

• For 'Explain LEGB scoping in Python.', a strong interview answer should define the mechanism, name the common failure mode, and explain the production decision it affects
• Interviewers look for the practical consequences: late binding in closures, UnboundLocalError when assigning to a name that was expected to be global, and when nonlocal is appropriate for nested functions
• Relevant areas: Python, Core
• Use the answer to connect the concept back to a realistic production or interview scenario for 'Explain LEGB scoping in Python.'

Comparison / Tradeoffs