一开始我在考虑使用一个通用的整数列表和list.Exists()方法,但这是O(n);然后我在考虑使用字典和ContainsKey方法。但是,我只需要键,我不需要值。我认为这也是一个线性搜索。是否有更好的数据类型可用于查找列表中的唯一性?或者我坚持使用线性搜索? 浏览2提问于2009-08-21得票数 0 回答已采纳 1回答 ...
Check if an element exists in a list in Python by leveraging various efficient methods, each suited to different scenarios and requirements. This article will guide you through the multitude of ways to determine the presence of an element within a list, ranging from the straightforward in operator...
# 定义一个集合my_set={1,2,3,4,5}# 添加元素到集合my_set.add(6)print(my_set)# 输出: {1, 2, 3, 4, 5, 6}# 删除集合中的元素my_set.remove(3)print(my_set)# 输出: {1, 2, 4, 5, 6}# 检查元素是否在集合中if 4 in my_set:print('Element exists')# 输出: Element exists 2...
I'd like to check if this file name exists in any of the directories, if it does exist then the code passes, if not then we'll error out. I'm having some trouble with the next step though, here's what I have. for value in d.values(): for path in value: if exists(path + ...
There are 7 columns in my dataframe and I check if value exists in each column compared to the column on the left. It works out fine using .isin() method. The problem is that I need to check if value exists in column A or column B to place a True or False value on my ...
Python 判断元素是否在列表中存在 Python3 实例 定义一个列表,并判断元素是否在列表中。 实例 1 [mycode4 type='python'] test_list = [ 1, 6, 3, 5, 3, 4 ] print('查看 4 是否在列表中 ( 使用循环 ) : ') for i in test_list: if(i == 4) : ..
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if my_list will return true if the list is not empty. Of course, there are other ways to check if a list is empty like verifying its length and comparing it directly to another empty list.If that’s all you needed, help grow the site by visiting my list of ways to support The Ren...
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However, no mutable sequence or object can be used as a key, like a list. In this article, we'll take a look at how to check if a key exists in a dictionary in Python. In the examples, we'll be using this fruits_dict dictionary: fruits_dict = dict(apple= 1, mango= 3, ...