Implementation method of python tuple unpacking

1. Description

Putting out tuple 11 correspondingly is called tuple unpacking. Unpacking has a requirement that the number of elements in the tuple must be equal to the number of nulls that accept these elements, otherwise an error will be reported:

tuple_test = (1, 2, 3)

a, b = tuple_test # ValueError: too many values to unpack (expected 2)

2. Examples

_ Placeholder

Use the _ placeholder to solve this problem:

tuple_test = (1, 2, 3)
a, b, _ = tuple_test

In this way, only part of the data is obtained, which is especially useful when taking the return value of the function, such as:

import os

_, filename = os.path.split("/home/dongfanger/.ssh/idrsa.pub")
print(filename) # "idrsa.pub"

Extension of basic knowledge points:

Tuples?

Characteristics of tuples:

Equivalent to an immutable list;

Can be used for records without field names.

The tuple in pythn is equivalent to the array in C language, which is immutable, but can also accommodate different types of elements, and is also a kind of container.

>>> t = (1,2,'a','b','c')
>>> t
(1, 2, 'a', 'b', 'c')
>>> type(t)
<class 'tuple'>

There are two main methods for tuples:

index (): Gets the subscript of the specified element within the tuple count (): Counts the number of occurrences of the specified element within the tuple

The definition and structure of a tuple is similar to a list, but it is relatively simple to use, and the elements of a tuple are contained with '()'.

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