如何在c#中更新字典中键的值？
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How to update value of a key in dictionary in c#?
提问by Ahsan Ashfaq
I have the following code in c# , basically it's a simple dictionary with some keys and their values.
我在 c# 中有以下代码，基本上它是一个带有一些键及其值的简单字典。
Dictionary<string, int> dictionary =
new Dictionary<string, int>();
dictionary.Add("cat", 2);
dictionary.Add("dog", 1);
dictionary.Add("llama", 0);
dictionary.Add("iguana", -1);
I want to update the key 'cat' with new value 5.
How could I do this?
我想用新值5更新键 'cat' 。
我怎么能这样做？
回答by J0HN
Have you tried just
你有没有试过
dictionary["cat"] = 5;
:)
:)
Update
更新
dictionary["cat"] = 5+2;
dictionary["cat"] = dictionary["cat"]+2;
dictionary["cat"] += 2;
Beware of non-existing keys:)
当心不存在的密钥:)
回答by yamen
Just use the indexer and update directly:
只需使用索引器并直接更新：
dictionary["cat"] = 3
回答by cubski
Try this simple function to add an dictionary item if it does not exist or update when it exists:
试试这个简单的函数来添加一个字典项，如果它不存在或在它存在时更新：
public void AddOrUpdateDictionaryEntry(string key, int value)
{
if (dict.ContainsKey(key))
{
dict[key] = value;
}
else
{
dict.Add(key, value);
}
}
This is the same as dict[key] = value.
这与 dict[key] = value 相同。
回答by Nikhil Agrawal
Dictionary is a key value pair. Catch Key by
字典是一个键值对。抓住关键
dic["cat"]
and assign its value like
并分配其值，例如
dic["cat"] = 5
