如何将项目从字典复制到另一个字典？

Question

Dictionary<string, List<string>> list1= new Dictionary<string, List<string>>();
Dictionary<string, List<string>> list2= new Dictionary<string, List<string>>();

我想根据条件将list1的项目复制到list2中：

foreach (var confirmNumber in list1.Keys)
{                                
    if (condition)
    {                                    
        list2.Add(confirmNumber,list1[confirmNumber]);
    }
}

它实际上不会起作用。

Answer 1

所以你只想从符合给定条件的列表中获取项目吗？

Dictionary<string, List<string>> list2 = list1
    .SelectMany(kv => kv.Value.Select(s => new { kv.Key, s }))
    .Where(x => condition) // you have the key and the string to apply the condition
    .GroupBy(x => x.Key)
    .ToDictionary(g => g.Key, g => g.Select(x => x.s).ToList());