python元组打包和解包过程详解_Python

python元组打包和解包过程详解

2021-12-16 00:42小妮浅浅 Python

在本篇文章里，我们给大家整理了关于python元组打包和解包过程的知识点内容，有兴趣点的朋友们可以跟着学习下。

1、在将多个以逗号分隔的值赋给一个变量时，多个值被打包成一个元组类型。当我们将一个元组赋给多个变量时，它将解包成多个值，然后分别将其赋给相应的变量。

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									# 打包

									a = 1, 10, 100

									print(type(a), a)    # <class 'tuple'> (1, 10, 100)

									# 解包

									i, j, k = a

									print(i, j, k)       # 1 10 100

2、解包时，如果解包出来的元素数目与变量数目不匹配，就会引发ValueError异常。错误信息为：too many values to unpack（解包的值太多）或not enough values to unpack（解包的值不足）。

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									a = 1, 10, 100, 1000

									# i, j, k = a             # ValueError: too many values to unpack (expected 3)

									# i, j, k, l, m, n = a    # ValueError: not enough values to unpack (expected 6, got 4)

知识点扩充：

python之打包，解包

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									#coding:utf-8

									#字符串，列表，元组打包与解包

									aString = 'abc'

									aList = [1, 2, 3]

									aTuple = 'a', 'A', 1

									print('Unpacking string......')

									first, second, third = aString

									print("string values:", first, second, third)

									print('\nUnpacking list......')

									first, second, third = aList

									print("string values:", first, second, third)

									print('\nUnpacking tuple......')

									first, second, third = aTuple

									print("string values:", first, second, third)

									#swapping two values

									x = 3

									y = 4

									print('\nBefore swapping: x = %d,y =%d' % (x, y))

									#首先将右边的部分打包成一个元组，即（4，3），而后解包指派给变量x,y

									x, y = y, x #swap Variables

									print('After swapping: x = %d, y = %d' % (x, y))