Python notes----deconstruction and encapsulation

Elements are refactored on the left and the elements on the right are encapsulated

Encapsulation: Defines a tuple, you can omit parentheses, the encapsulated must be a tuple

X, y = y, X

Deconstruction: Assigning elements of linear deconstruction to variables in order of elements

the deconstruction changes in Python3

You can accept all elements by using the asterisk * plus a variable

Can not use the asterisk as a single variable to receive, if you can, the equivalent of lst[0:0]

In the same deconstruction, only one asterisk can be used

When the left variable exceeds the number of elements on the right, it is not allowed

The elements must match the number of variables and the number of elements in order to be matched with an asterisk variable, you can accept any number of elements plus an asterisk variable cannot appear in Python alone, using an underscore _ _ to discard the variable

A single underline is a legitimate identifier for Python, but if you are not dropping a variable, you usually don't use a single underline to represent a meaningful variable

_, (*_, tail), *_ = LST #解构是支持多层的