排列一系列可能为空的字符串变量的最简洁方法是什么

I need to array an ad-hoc set of strings like this

我需要像这样排列一组特殊的字符串

string a = null;
string b = "include me";
string c = string.Empty;
string d = "me too!";

without including null or empty strings. I know I can use a child function and params:

不包括null或空字符串。我知道我可以使用子函数和params：

private List<string> GetUniqueKeys(params string[] list)
{
    var newList = new List<string>();
    foreach (string s in list)
    {
        if (!string.IsNullOrWhiteSpace(s))
            newList.Add(s);
    }
    return newList;
}

///

return this.GetUniqueKeys(a, b, c, d).ToArray();

but is there any simpler way to do this that I'm not seeing?

但有没有更简单的方法来做到这一点，我没有看到？

EDIT: Sorry about that, happy to vote up the first LINQer, but I should have specified that I was trying to get rid of the child method altogether, not simplify it.

编辑：很抱歉，很高兴投票给第一个LINQer，但我应该指定我试图完全摆脱子方法，而不是简化它。

4 个解决方案

#1

No Child Function

没有儿童功能

The shortest way you can do this without a child function is the following:

没有子功能的最短方法是：

var a = new string[] { a, b, c, d }.Where(s => !string.IsNullOrWhiteSpace(s));

With Child Function

有儿童功能

However, I would recommend using your child function:

但是，我建议使用您的子功能：

private IEnumerable<string> GetUniqueKeys(params string[] list)
{
    return list.Where(s => !string.IsNullOrWhitespace(s));
}

Extension Method

扩展方法

Alternatively, if you're really looking for other options... you could create an extension method:

或者，如果您真的在寻找其他选项......您可以创建一个扩展方法：

public static List<string> AddIfNotEmpty(this List<string> list, params string[] items)
{
    list.AddRange(items.Where(s => !string.IsNullOrEmpty(s)));

    return list;
}

Then use it like such:

然后像这样使用它：

var list = new List<string>().AddIfNotEmpty(a, b, c, d);

And add other items later:

并在以后添加其他项目：

list.AddIfNotEmpty("new item", string.Empty);

#2

If the input strings are enumerable, you can use linq.

如果输入字符串是可枚举的，则可以使用linq。

var result = stringList.Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();

#3

private List<string> GetUniqueKeys(params string[] list)
{
    var newList = new List<string>();
    newList.AddRange(list.Where(str => !string.IsNullOrEmpty(str)));

    return newList;
}

#4

With Child method..

用Child方法..

private List<string> GetUniqueKeys(params string[] list)
{
    return list.Where(x => !string.IsNullOrWhiteSpace(x)).ToList();
}

Without Child method..

没有儿童方法..

string a = null;
string b = "include me";
string c = string.Empty;
string d = "me too!";

string[] lst = { a, b, c, d };
var uniqueLst = lst.Where(x => !string.IsNullOrWhiteSpace(x)).ToList(); //Or ToArray();

I recommend to use child method with params.

我建议使用params的子方法。

#1