Python |列表中的元素重复
原文:https://www . geesforgeks . org/python-element-repeat-in-list/
有时我们需要在列表中为几个不同的实用程序添加一个重复的值。这种类型的应用程序在日常编程中有时是必需的。让我们讨论一下将一个数字的克隆添加到下一个位置的某些方法。
方法#1:使用列表理解 在这个方法中，我们只需对每个值重复循环两次，并添加到所需的新列表中。这只是简单方法的一种替代。
# Python3 code to demonstrate
# to perform element duplication
# using list comprehension
# initializing list
test_list = [4, 5, 6, 3, 9]
# printing original list
print ("The original list is : " + str(test_list))
# using list comprehension
# to perform element duplication
res = [i for i in test_list for x in (0, 1)]
# printing result
print ("The list after element duplication " + str(res))
输出:
The original list is : [4, 5, 6, 3, 9]
The list after element duplication [4, 4, 5, 5, 6, 6, 3, 3, 9, 9]
方法 2:使用 reduce() + add**** 我们还可以使用 reduce 函数来充当函数，在列表中同时执行一对相似数字的加法。
# Python3 code to demonstrate
# to perform element duplication
# using reduce() + add
from operator import add
# initializing list
test_list = [4, 5, 6, 3, 9]
# printing original list
print ("The original list is : " + str(test_list))
# using reduce() + add
# to perform element duplication
res = list(reduce(add, [(i, i) for i in test_list]))
# printing result
print ("The list after element duplication " + str(res))
输出:
The original list is : [4, 5, 6, 3, 9]
The list after element duplication [4, 4, 5, 5, 6, 6, 3, 3, 9, 9]
方法 3:使用itertools.chain().from_iterable()
from_iterable 函数也可以执行这个添加副本的任务。它只是生成每个迭代元素的对，并将其连续插入。
# Python3 code to demonstrate
# to perform element duplication
# using itertools.chain.from_iterable()
import itertools
# initializing list
test_list = [4, 5, 6, 3, 9]
# printing original list
print ("The original list is : " + str(test_list))
# using itertools.chain.from_iterable()
# to perform element duplication
res = list(itertools.chain.from_iterable([i, i] for i in test_list))
# printing result
print ("The list after element duplication " + str(res))
输出:
The original list is : [4, 5, 6, 3, 9]
The list after element duplication [4, 4, 5, 5, 6, 6, 3, 3, 9, 9]
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