Global statement
A global statement is a Python declaration that makes specified names in a function refer to bindings in the module-level global namespace.
Python How-To
The global keyword declares that assignments to a name in a function refer to the corresponding binding in the global scope.
- How it is used
- Uses a function to update a module-level configuration value or other global binding.
- How deep it goes
- Explains LEGB resolution, local namespaces, and successful assignment without descending into interpreter internals.
- Examples
- Demonstrates changing db_filename and selecting the app_db database option.
- What you can do after
- Apply it to update a global variable from a function and diagnose why an unqualified assignment stays local.
Python Workout, Second Edition
The global statement declares that assignments and name accesses in a function refer to a module-level global name.
- How it is used
- Declares that a function's name retrievals and assignments target a module-level global variable.
- How deep it goes
- Distinguishes local assignment from global assignment and explains why list or dictionary item mutation differs.
- Examples
- Uses contrasting `x` examples showing local shadowing and explicit global reassignment.
- What you can do after
- Apply it via Python syntax to update a module-level name from inside a function when necessary.
Read how Python Workout, Second Edition explains global statement →
Python Workout: 50 ten-minute exercises
The global statement declares that assignments and references to specified names in a function use the module-level global bindings.
- How it is used
- Controls whether function assignments and references target local names or module-level global bindings.
- How deep it goes
- Explains declaration behavior with runnable examples and cautions against global mutation, without developing implementation internals.
- Examples
- Uses contrasting x bindings and a function that changes x through global.
- What you can do after
- Apply it via Python to update a module-level binding from inside a function when necessary.
Read how Python Workout: 50 ten-minute exercises explains global statement →
Related concepts
- global variableconfigures · A global variable is a variable whose binding is accessible from broad program or module scope according to the language’s name-resolution rules.
- nonlocal statementcontrasts with · A nonlocal statement makes a name assigned in a nested Python function refer to a binding in an enclosing function scope.
- bindingconfigures · Name binding is the association of an identifier with the program entity or value it denotes.
- scopeuses · Scope is the region of a program in which names are visible and can be resolved according to the language’s lookup rules.
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