all Python 3astterm

ast.Store

variables

The "store" context of Name, Attribute, Subscript, Starred, List and Tuple: the node is an assignment target, a for target or a with … as target.

Syntax

ast.Store()

Store appears not only in x = 1: the target is also marked Store in x += 1, for x in …, with f() as x and (x := 1), while import uses alias with a plain string instead. The parser reuses a single Store object for every node, so node.ctx is other_ctx is true; never set attributes on a ctx, the change leaks across the tree. Test isinstance(node.ctx, ast.Store) rather than comparing with ast.Store().

Examples

import ast
tree = ast.parse('for i in items:\n    total += i')
stored = [n.id for n in ast.walk(tree) if isinstance(n, ast.Name) and isinstance(n.ctx, ast.Store)]
print(sorted(stored))  # → ['i', 'total']

import ast
a = ast.parse('x = 1').body[0].targets[0].ctx
b = ast.parse('y = 2').body[0].targets[0].ctx
print(a is b, a == ast.Store())  # → True False

See also

Open in the full glossarydocs.python.orgReport an inaccuracy