Trailing comma produces a tuple, not the intended object

  • comma
  • tuple
  • assignment

Compare the following two assignemnts

In [1]: x = 1

In [2]: print(x)
1

In [3]: x = 2,

In [4]: print(x)
(2,)

In the former, x is assigned to be an integer 1. In the latter, however, x is assigned to be a tuple containing the integer 2.