コメントでbennofsが述べたintern()
ように、同じ文字列が一度だけ保存されるようにするために使用できます。
class InternDict(dict):
def __setitem__(self, key, value):
if isinstance(value, str):
super(InternDict, self).__setitem__(key, intern(value))
else:
super(InternDict, self).__setitem__(key, value)
効果の例を次に示します。
>>> d = {}
>>> d["a"] = "This string is presumably too long to be auto-interned."
>>> d["b"] = "This string is presumably too long to be auto-interned."
>>> d["a"] is d["b"]
False
>>> di = InternDict()
>>> di["a"] = "This string is presumably too long to be auto-interned."
>>> di["b"] = "This string is presumably too long to be auto-interned."
>>> di["a"] is di["b"]
True