TheDeveloperBlog.com

Home | Contact Us

C-Sharp | Java | Python | Swift | GO | WPF | Ruby | Scala | F# | JavaScript | SQL | PHP | Angular | HTML

<< Back to C-SHARP

C# ToString Integer Optimization

Optimize the ToString method on integers. Reduce string allocations.
ToString can be optimized for ints. It actually allocates a new string each time it is called on an int variable. We use an extension method. We use a lookup table and avoid this allocation in some cases.
Example. First we demonstrate code that introduces an extension method called ToStringLookup. This method can be used on any integer variable to use the ToString method only if the string is not found in the lookup table.

Internally: The ToStringExtensions class stores a static string array: the lookup table. It contains 200 string literals in the metadata.

ArrayString Literal

Then: The ToStringLookup extension method checks for values that are in the lookup table, and otherwise calls ToString.

Info: The ToStringLookup method is introduced in the ToStringExtensions static class. It uses the extension method syntax.

ToStringLookup: This returns a string representation of each integer, as ToString would. But it avoids an allocation for two of the calls.

Extension method class file: C# using System.Globalization; static class ToStringExtensions { // Lookup table. static string[] _cache = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "70", "71", "72", "73", "74", "75", "76", "77", "78", "79", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "90", "91", "92", "93", "94", "95", "96", "97", "98", "99", "100", "101", "102", "103", "104", "105", "106", "107", "108", "109", "110", "111", "112", "113", "114", "115", "116", "117", "118", "119", "120", "121", "122", "123", "124", "125", "126", "127", "128", "129", "130", "131", "132", "133", "134", "135", "136", "137", "138", "139", "140", "141", "142", "143", "144", "145", "146", "147", "148", "149", "150", "151", "152", "153", "154", "155", "156", "157", "158", "159", "160", "161", "162", "163", "164", "165", "166", "167", "168", "169", "170", "171", "172", "173", "174", "175", "176", "177", "178", "179", "180", "181", "182", "183", "184", "185", "186", "187", "188", "189", "190", "191", "192", "193", "194", "195", "196", "197", "198", "199" }; // Lookup table last index. const int _top = 199; public static string ToStringLookup(this int value) { // See if the integer is in range of the lookup table. // ... If it is present, return the string literal element. if (value >= 0 && value <= _top) { return _cache[value]; } // Fall back to ToString method. return value.ToString(CultureInfo.InvariantCulture); } } C# program that uses extension method using System; class Program { static void Main() { // Use the ToString lookup extension method. Console.WriteLine((-100).ToStringLookup()); Console.WriteLine(5.ToStringLookup()); Console.WriteLine(199.ToStringLookup()); Console.WriteLine(200.ToStringLookup()); } } Output -100 5 199 200
Performance. The ToString lookup method shown in this article is much faster when you call ToString on an integer of value 0 to 199. In that range, a string literal is simply returned. This avoids an entire heap allocation.

Note: In the .NET Framework, a string requires 20 bytes of memory as well as 2 bytes for each character.

Tip: The ToStringLookup method avoids this overhead on multiple values of 0-199.

String Performance
Also, the method shown above only stores the first 200 strings in the metadata as string literals. You can store many more strings. This would also help performance. You could generate a C# file with code.

Further: You could use a Dictionary. But this could introduce threading problems. It might cause extreme memory usage.

Dictionary

Results: In my tests, a ToString call on a zero integer requires about 100 ns. A ToStringLookup call on a zero requires about 3 ns.

Summary. We looked at a C# cache class that can store common string representations of integers. The ToStringLookup method can then be used to optimize the conversion of integers to strings.ToStringOptimization
© TheDeveloperBlog.com
The Dev Codes

Related Links:


Related Links

Adjectives Ado Ai Android Angular Antonyms Apache Articles Asp Autocad Automata Aws Azure Basic Binary Bitcoin Blockchain C Cassandra Change Coa Computer Control Cpp Create Creating C-Sharp Cyber Daa Data Dbms Deletion Devops Difference Discrete Es6 Ethical Examples Features Firebase Flutter Fs Git Go Hbase History Hive Hiveql How Html Idioms Insertion Installing Ios Java Joomla Js Kafka Kali Laravel Logical Machine Matlab Matrix Mongodb Mysql One Opencv Oracle Ordering Os Pandas Php Pig Pl Postgresql Powershell Prepositions Program Python React Ruby Scala Selecting Selenium Sentence Seo Sharepoint Software Spellings Spotting Spring Sql Sqlite Sqoop Svn Swift Synonyms Talend Testng Types Uml Unity Vbnet Verbal Webdriver What Wpf