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pythondictionarydatamodel

Why can't I call del [:] on a dict?

What's going on here?

>>> a = {1: "a", 2: "b"}
>>> del a[1]
>>> a
{2: 'b'}
>>> a = {1: "a", 2: "b"}
>>> del a[:]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type
>>> a.clear()
>>> a
{}

Why must I call dict.clear?

Solution

  • a[:] is a special case of a slicing operation, which is defined only for sequences. It is a short form of a[0:len(a)]. A dict is not a sequence.