C# 字符串比较效率

最新推荐文章于 2024-03-05 12:42:06 发布

原创最新推荐文章于 2024-03-05 12:42:06 发布 · 904 阅读

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#c# #string #字符串比较

自用草稿，勿参考

        private void btn_start_Click(object sender, EventArgs e)
        {
            Console.WriteLine("START");
            for (int i = 0; i < 10; i++)
            {
                testVoid();
                Console.WriteLine("");
            }
            Console.WriteLine("All Clear");
            Console.WriteLine("==: " + (float)r1 / 10);
            Console.WriteLine("str.Equals: " + (float)r2 / 10);
            Console.WriteLine("str.CompareTo: " + (float)r3 / 10);
            Console.WriteLine("string.Compare: " + (float)r4 / 10);
            Console.WriteLine("string.CompareOrdinal: " + (float)r5 / 10);
            Console.WriteLine("string.Equals: " + (float)r6 / 10);
        }

private static int r1 = 0, r2 = 0, r3 = 0, r4 = 0, r5 = 0, r6 = 0;

        private static void testVoid()
        {
            int start = Environment.TickCount;
            int total = 0;
            string orgString = FixedFunc.getRandText(49);
            List<string> strList = new List<string>();

            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (str == orgString)
                    Console.WriteLine("This is 1");
            }
            total = (Environment.TickCount - start);
            r1 += total;
            Console.WriteLine("== OVER: " + total);

            strList.Clear();
            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (str.Equals(orgString) == true)
                    Console.WriteLine("This is 2");
            }
            total = (Environment.TickCount - start);
            r2 += total;
            Console.WriteLine("str.Equals OVER: " + total);

            strList.Clear();
            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (str.CompareTo(orgString) == 0)
                    Console.WriteLine("This is 3");
            }
            total = (Environment.TickCount - start);
            r3 += total;
            Console.WriteLine("str.CompareTo OVER: " + total);

            strList.Clear();
            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (string.Compare(str, orgString) == 0)
                    Console.WriteLine("This is 4");
            }
            total = (Environment.TickCount - start);
            r4 += total;
            Console.WriteLine("string.Compare OVER: " + total);

            strList.Clear();
            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (string.CompareOrdinal(str, orgString) == 0)
                    Console.WriteLine("This is 5");
            }
            total = (Environment.TickCount - start);
            r5 += total;
            Console.WriteLine("string.CompareOrdinal OVER: " + total);

            strList.Clear();
            for (int i = 0; i < 1000000; i++)
            {
                strList.Add(FixedFunc.getRandText(49));
            }
            start = Environment.TickCount;
            foreach (string str in strList)
            {
                if (string.Equals(str, orgString) == true)
                    Console.WriteLine("This is 6");
            }
            total = (Environment.TickCount - start);
            r6 += total;
            Console.WriteLine("string.Equals OVER: " + total);
        }

结果：

START
== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 375
string.Compare OVER: 375
string.CompareOrdinal OVER: 47
string.Equals OVER: 31

== OVER: 31
str.Equals OVER: 31
str.CompareTo OVER: 375
string.Compare OVER: 359
string.CompareOrdinal OVER: 31
string.Equals OVER: 47

== OVER: 32
str.Equals OVER: 47
str.CompareTo OVER: 406
string.Compare OVER: 375
string.CompareOrdinal OVER: 31
string.Equals OVER: 47

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 375
string.Compare OVER: 375
string.CompareOrdinal OVER: 31
string.Equals OVER: 47

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 375
string.Compare OVER: 375
string.CompareOrdinal OVER: 47
string.Equals OVER: 31

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 375
string.Compare OVER: 391
string.CompareOrdinal OVER: 31
string.Equals OVER: 47

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 391
string.Compare OVER: 375
string.CompareOrdinal OVER: 47
string.Equals OVER: 31

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 406
string.Compare OVER: 375
string.CompareOrdinal OVER: 47
string.Equals OVER: 47

== OVER: 47
str.Equals OVER: 47
str.CompareTo OVER: 375
string.Compare OVER: 375
string.CompareOrdinal OVER: 47
string.Equals OVER: 31

== OVER: 47
str.Equals OVER: 31
str.CompareTo OVER: 375
string.Compare OVER: 375
string.CompareOrdinal OVER: 31
string.Equals OVER: 31

All Clear
==: 43.9
str.Equals: 43.8
str.CompareTo: 382.8
string.Compare: 375
string.CompareOrdinal: 39
string.Equals: 39

结论：

在我的电脑上

比较是否相等最好用 string.equals

比较大小最好用 string.CompareOrdinal