如何判断格式化字符串中的替换次数？

发布于 2024-09-06 02:44:13 字数 323 浏览 2 评论 0原文

给出以下方法：（真正的方法还有一些参数，但重要的参数如下...）

public string DoSomething(string formatter, params string[] values)
{
    // Do something eventually involving a call to String.Format(formatter, values);
}

有没有办法判断我的值数组中是否有足够的对象来覆盖格式化程序，以便我可以抛出一个如果没有（缺少执行 string.Format ；由于某些 lambda 转换，直到最后都不是一个选项）？

原文

Given the following method: (real method has a few more parameters, but the important ones are below...)

public string DoSomething(string formatter, params string[] values)
{
    // Do something eventually involving a call to String.Format(formatter, values);
}

Is there a way to tell if my values array has enough objects in it to cover the formatter, so that I can throw an exception if there aren't (short of doing the string.Format; that isn't an option until the end due to some lambda conversions)?

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陌路终见情 2024-09-13 02:44:13

我仍然不清楚为什么您认为不能使用 string.Format 来测试它。如果传入的格式化程序应该具有值中项目的占位符，那么您应该能够执行以下操作：

static void TestFormat(string formatter, params string[] values)
{
    try
    {
        string.Format(formatter, values);
    }
    catch (FormatException e)
    {
        throw new Exception("the format is bad!!", e);
    }
}

示例用法：

        TestFormat("{0}{1}{2}", "a", "b", "c"); // works ok
        TestFormat("{0}{1}{2}", "a", "b"); // throws exception
        TestFormat("{0}{1}{2}}0{", "a", "b", "c"); // throws exception

尝试使用正则表达式执行此操作将会很困难，因为像这样的事情怎么样：

"{0}, {1}, {abc}, {1a4} {5} }{"

< code>{abc} 和 {1a4} 对于 string.Format 无效，您还必须确定每个有效数字 ({0}、{1}、{5}）表明您至少有那么多参数。此外， }{ 也会导致 string.Format 失败。

我刚刚在最近的一个项目中使用了上面描述的前一种方法，效果很好。

I'm still not clear why you think you cannot use string.Format to test it. If the passed in formatter is supposed to have placeholders for the items in values, then you should be able to do this:

static void TestFormat(string formatter, params string[] values)
{
    try
    {
        string.Format(formatter, values);
    }
    catch (FormatException e)
    {
        throw new Exception("the format is bad!!", e);
    }
}

Sample Usage:

        TestFormat("{0}{1}{2}", "a", "b", "c"); // works ok
        TestFormat("{0}{1}{2}", "a", "b"); // throws exception
        TestFormat("{0}{1}{2}}0{", "a", "b", "c"); // throws exception

Trying to do this with a regular expression is going to be tough, because what about something like this:

"{0}, {1}, {abc}, {1a4} {5} }{"

{abc} and {1a4} aren't valid for string.Format, and you also have to determine for each valid number ({0}, {1}, {5}) that you have at least that many arguments. Also, the }{ will cause string.Format to fail as well.

I just used the former approach described above in a recent project and it worked great.

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