如何只從字符串數組中獲取數字？

Question

我有一個包含數字和單詞的字符串（ items ）數組 - 我從一個包含int和string值的字典（ matches ）中提取它。 我想得到一個數組或我可以循環的東西，它只包含數字，按數字排序，然后在控制台中顯示它們。

通過使用正則表達式，我可以很容易地為單個字符串執行此操作，但是當我有一個字符串數組時，我不知道該怎么做。

下面的代碼，見評論：

var matches = new Dictionary<int, string>();
matches.Add(1, "value1");
matches.Add(2, "value5");
matches.Add(3, "value2");
var items = matches.Values.ToArray();
Array.Sort(items, StringComparer.CurrentCulture);
Regex rgx = new Regex(@"\D");
rgx.Replace(items, ""); //This doesn't work with arrays!
int[] numbers = Array.ConvertAll(items, s => int.Parse(s)); //This doesn't work because my strings still contain letters
foreach (int c in numbers)
{
    Console.WriteLine(string.Format("Number is {0}", c));
    Console.ReadKey();
}

期望的輸出是：

Number is 1
Number is 5
Number is 2

如果不明顯，這些數字來自value1 、 value5和value2 。

Answer 1

您可以使用 LINQ 來完成。 該表達式非常具有聲明性且不言自明：

// we're searching for digits, not removing non-digits as in your example
Regex regex = new Regex(@"\d+");

var results = matches.Values
    .Select(v => regex.Match(v))     // do regex on each item
    .Where(m => m.Success)           // select only those results where regex worked
    .Select(m => int.Parse(m.Value)) // convert to int
    .ToList();                       // convert the results to a list - if you want to sort it

// you wanted to sort the list, right?
results.Sort();

foreach (int number in results)
{
    Console.WriteLine($"Number is {number}");
}

Answer 2

用List<T>而不是 Array 來做這件事會讓事情變得更容易！

var matches = new Dictionary<int, string>();
matches.Add(1, "value1");
matches.Add(2, "value5");
matches.Add(3, "value2");

var items = matches.Values.ToList();
items.Sort( StringComparer.CurrentCulture);
Regex rgx = new Regex(@"\D");
var numbers = items.Select(i => int.Parse(rgx.Replace(i, "")));

foreach (int c in numbers)
{
    Console.WriteLine(string.Format($"Number is {c}"));
}

Answer 3

這是一個使用 Regex 的示例：

            string[] input = { "Number is 1", "Number is 5", "Number is 2" };
            string pattern = @"\d+";

            int[] results = input.Select(x => Regex.Match(x, pattern)).Cast<Match>().Select(x => int.Parse(x.Value)).ToArray();