我需要比較檔案中的部分編號，起初我只是要轉換為十進制并檢查一個數字是否大于另一個。問題是某些部分有多個小數。
示例：我需要對 1.1 和 1.1.2.3 進行數學比較，以確定檔案中哪個更靠前。
它們首先是字串，我需要對它們進行一些數學比較。我想洗掉小數然后轉換為 int 但這會拋出某些部分，例如第 2 部分將被視為小于 1.1 部分，因為 1.1 將更改為 11，這是不好的。
string section1 = "1.1";
string section2 = "2";
int convertedSection1 = Convert.ToInt32(section1.Replace(".",""));
int convertedSection2 = Convert.ToInt32(section2.Replace(".",""));
if(convertedSection1 < convertedSection2)
//This will incorrectly say 1.1 is greater than 2
string section1 = "1.1.2.4";
string section2 = "2.4";
decimal convertedSection1 = Convert.ToDecimal(section1);
decimal convertedSection2 = Convert.ToDecimal(section2);
if(convertedSection1 < convertedSection2)
//This will convert 1.1.2.4 to 1.1 which is no good
uj5u.com熱心網友回復：
您可以創建一個類似于Version.NET 框架類的類。如果你實作了一些運算子 and IComparable，那真的很好。
它是如何作業的？它會將給定的字串轉換為整數串列。比較時，它將從每個串列的開頭開始并比較每個單獨的部分。
public class Section: IComparable<Section>
{
// Stores all individual components of the section
private List<int> parts = new List<int>();
// Construct a section from a string
public Section(string section)
{
var strings = section.Split('.');
foreach (var s in strings)
{
parts.Add(int.Parse(s));
}
}
// Make it nice for display
public override string ToString()
{
return string.Join(".", parts);
}
// Implement comparison operators for convenience
public static bool operator ==(Section a, Section b)
{
// Comparing the identical object
if (ReferenceEquals(a, b)) return true;
// One object is null and the other isn't
if ((object)a == null) return false;
if ((object)b == null) return false;
// Different amount of items
if (a.parts.Count != b.parts.Count) return false;
// Check all individual items
for (int i=0; i<a.parts.Count;i )
{
if (a.parts[i] != b.parts[i]) return false;
}
return true;
}
public static bool operator !=(Section a, Section b)
{
return !(a == b);
}
public static bool operator <(Section a, Section b)
{
// Use minimum, otherwise we exceed the index
for (int i=0; i< Math.Min(a.parts.Count, b.parts.Count); i )
{
if (a.parts[i] < b.parts[i]) return true;
}
if (b.parts.Count > a.parts.Count) return true;
return false;
}
public static bool operator >(Section a, Section b)
{
// Use minimum, otherwise we exceed the index
for (int i = 0; i < Math.Min(a.parts.Count, b.parts.Count); i )
{
if (a.parts[i] > b.parts[i]) return true;
}
if (a.parts.Count > b.parts.Count) return true;
return false;
}
// Implement the IComparable interface for sorting
public int CompareTo(Section other)
{
if (this == other) return 0;
if (this < other) return -1;
return 1;
}
}
96% 覆寫率的測驗：
Assert.IsTrue(new Section("1.2.3.4") > new Section("1.2.3"));
Assert.IsFalse(new Section("1.2.3.4") < new Section("1.2.3"));
Assert.IsFalse(new Section("1.2.3.4") == new Section("1.2.3"));
Assert.IsTrue(new Section("1.2.3.4") == new Section("1.2.3.4"));
Assert.IsFalse(new Section("1.2.3.4") == new Section("1.2.3.5"));
Assert.IsTrue(new Section("1.2.3.4") != new Section("1.2.3.5"));
var sec = new Section("1");
Assert.IsTrue(sec == sec);
Assert.AreEqual("1.2.3.4", new Section("1.2.3.4").ToString());
var sortTest = new List<Section> { new Section("2"), new Section("1.2"), new Section("1"), new Section("3.1") };
sortTest.Sort();
var expected = new List<Section> { new Section("1"), new Section("1.2"), new Section("2"), new Section("3.1") };
CollectionAssert.AreEqual(expected, sortTest, new SectionComparer());
uj5u.com熱心網友回復：
如果您知道您的部分字串總是格式良好，并且您知道它們不超過 6 個級別，并且沒有一個級別超過 999 個專案，那么這很有效：
string zero = ".0.0.0.0.0.0";
long Section2Long(string section) =>
(section zero)
.Split('.')
.Take(6)
.Select(t => long.Parse(t))
.Aggregate((x, y) => x * 1000 y);
現在，如果我有這個：
string[] sections = new []
{
"1.2.4", "2.3", "1", "1.2", "1.1.1.1", "1.0.0.1.0.1", "2.2.9"
};
我可以像這樣輕松地對其進行排序：
string[] sorted = sections.OrderBy(x => Section2Long(x)).ToArray();
我得到這個輸出：
1
1.0.0.1.0.1
1.1.1.1
1.2
1.2.4
2.2.9
2.3
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