我有以下代码,其中i为字典中的每个样本分支,有没有一种方法可以通过使用LINQ或其他任何可以避免分支的方法->可能是一种功能性方法
Dictionary<string, int> samples = new Dictionary<string, int>()
{
{"a", 1},
{"aa", 2},
{"b", 1},
{"bb", 3}
};
foreach (var sample in samples)
{
if (sample.Value ==)
{
Console.WriteLine("sample passed");
}
else if (sample.Value == 2)
{
Console.WriteLine("sample isolated");
}
else if (sample.Value == 3)
{
Console.WriteLine("sample biased");
}
}
UPD
如果我有其他类型的夸张该怎么办?
foreach (var sample in samples)
{
if (sample.Value <= 1)
{
Console.WriteLine("sample passed");
}
else if (sample.Value <= 2)
{
Console.WriteLine("sample isolated");
}
else if (sample.Value <= 3)
{
Console.WriteLine("sample biased");
}
}
答案 0 :(得分:0)
一个选择是创建要执行的Action
列表,然后根据索引执行它们。这样,您的方法就可以多种多样。如果您需要为每个选项执行非常相似的操作,那么存储值列表会比存储操作更好。
List<Action> functions = new List<Action>();
functions.Add(() => Console.WriteLine("sample passed"));
functions.Add(() => Console.WriteLine("sample isolated"));
functions.Add(() => Console.WriteLine("sample biased"));
foreach (var sample in samples)
{
Action actionToExecute = functions[sample.Value - 1];
actionToExectute();
}
如果您想使用字典作为注释,则表示:
Dictionary<int, Action> functions = new Dictionary<int, Action>();
functions.Add(1, () => Console.WriteLine("sample passed"));
functions.Add(2, () => Console.WriteLine("sample isolated"));
functions.Add(3, () => Console.WriteLine("sample biased"));
foreach (var sample in samples)
{
Action actionToExecute = functions[sample.Value];
actionToExectute();
}
答案 1 :(得分:0)
对于这种具体情况,您可以引入另一个映射(像我一样{Dictionary
或数组):
Dictionary<string, int> samples = new Dictionary<string, int>()
{
{"a", 1},
{"aa", 2},
{"b", 1},
{"bb", 3}
};
var map = new []
{
"sample passed",
"sample isolated",
"sample biased"
};
foreach (var sample in samples)
{
Console.WriteLine(map[sample.Value - 1]);
}
对于实际代码,它很大程度上取决于用例以及您要如何处理错误情况。
UPD
看来,如果您仍要在地图上使用字典,will be some branching还是不错的选择,但是如果您不会错过任何机会,分支预测应该解决这一问题。
答案 2 :(得分:0)
因此,您有一个Dictionary<string, int>
。字典中的每个项目都是KeyValuePair<string, int>
。我假设字符串是样本(标识符)的名称,而int是表示样本内容的数字:
所有更高的数字对您来说都不有趣。
您要将样本分为“通过” /“隔离” /“有偏”样本。
每当您有一系列相似的项目并且想要组成一组项目时,其中每个元素与该组中的其他元素都有一些共同之处,请考虑使用Enumerable.GroupBy
让我们首先定义一个枚举来保存您的资格,以及一个将样本的整数值转换为枚举的方法:
enum SampleQualification
{
Passed,
Isolated,
Biased,
}
SampleQualification FromNumber(int number)
{
switch (number)
{
case 2:
return SampleQualification.Isolated;
case 3:
return SampleQualification.Biased;
default:
return SampleQualification.Passed;
}
}
好,因此您有样本字典,其中每个键都是样本的名称,值是可以转换为SampleQualification的数字。
Dictionary<string, int> samples = ...
var qualifiedSamples = samples // implements IEnumerable<KeyValuePair<string, int>>
// keep only samples with Value 0..3
.Where(sample => 0 <= sample.Value && sample.Value <= 3)
// Decide where the sample is Passed / Isolated / Biased
.Select(sample => new
{
Qualification = FromNumber(sample.Value)
Name = sample.Key, // the name of the sample
Number = sample.Value,
})
// Make groups of Samples with same Qualification:
.GroupBy(
// KeySelector: make groups with same qualification:
sample => sample.Qualification,
// ResultSelector: take the qualification, and all samples with this qualification
// to make one new:
(qualification, samplesWithThisQualification) => new
{
Qualification = qualification,
Samples = samplesWithThisQualification.Select(sample => new
{
Name = sample.Name,
Number = sample.Number,
})
.ToList(),
});
结果是一系列项目。每个项目都具有财产资格,该资格持有通过/隔离/有偏。每个项目还包含具有此资格的样品列表。
// Process Result
foreach (var qualifiedSample in qualifiedSamples)
{
Console.WriteLine("All samples with qualification " + qualifiedSample.Qualification);
foreach (var sample in qualifiedSample.Samples)
{
Console.WriteLine({0} - {1}, sample.Name, sample.Value);
}
}