我如何用c#优雅地做到这一点?

例如,一个数字可以是1到100之间。

我知道一个简单的if (x >= 1 && x <= 100)就足够了;但是有很多语法糖和新特性不断添加到c# /。Net这个问题是关于更习惯的(一个可以称之为优雅的)写法。

性能不是问题,但请在非O(1)的解决方案中添加性能说明,因为人们可能会复制粘贴建议。


当前回答

我不知道,但我用这个方法:

    public static Boolean isInRange(this Decimal dec, Decimal min, Decimal max, bool includesMin = true, bool includesMax = true ) {

    return (includesMin ? (dec >= min) : (dec > min)) && (includesMax ? (dec <= max) : (dec < max));
}

这是我使用它的方式:

    [TestMethod]
    public void IsIntoTheRange()
    {
        decimal dec = 54;

        Boolean result = false;

        result = dec.isInRange(50, 60); //result = True
        Assert.IsTrue(result);

        result = dec.isInRange(55, 60); //result = False
        Assert.IsFalse(result);

        result = dec.isInRange(54, 60); //result = True
        Assert.IsTrue(result);

        result = dec.isInRange(54, 60, false); //result = False
        Assert.IsFalse(result);

        result = dec.isInRange(32, 54, false, false);//result = False
        Assert.IsFalse(result);

        result = dec.isInRange(32, 54, false);//result = True
        Assert.IsTrue(result);
    }

其他回答

你在寻找[1..100]?这只是帕斯卡。

Using an && expression to join two comparisons is simply the most elegant way to do this. If you try using fancy extension methods and such, you run into the question of whether to include the upper bound, the lower bound, or both. Once you start adding additional variables or changing the extension names to indicate what is included, your code becomes longer and harder to read (for the vast majority of programmers). Furthermore, tools like Resharper will warn you if your comparison doesn't make sense (number > 100 && number < 1), which they won't do if you use a method ('i.IsBetween(100, 1)').

我要做的唯一另一个评论是,如果你检查输入的意图是抛出异常,你应该考虑使用代码契约:

Contract.Requires(number > 1 && number < 100)

这比if(…)抛出new Exception(…)更优雅,如果有人试图调用您的方法而没有首先确保该数字在边界内,您甚至可以得到编译时警告。

你的意思是?

if(number >= 1 && number <= 100)

or

bool TestRange (int numberToCheck, int bottom, int top)
{
  return (numberToCheck >= bottom && numberToCheck <= top);
}
if (value > 1 && value < 100)
{
    // do work
}
else
{
    // handle outside of range logic
}

新花样的老最爱:

public bool IsWithinRange(int number, int topOfRange, int bottomOfRange, bool includeBoundaries) {
    if (includeBoundaries)
        return number <= topOfRange && number >= bottomOfRange;
    return number < topOfRange && number > bottomOfRange;
}