Truncate. This C# method restricts the maximum length of strings. We truncate a string so that it has a substring of the first specified number of letters.
Truncate is useful for text in databases or in user interfaces where space is limited. It can be helpful when justifying text to the right as well.
Info By always entering the Substring method, we may create string copies that are not needed.
C# program that truncates strings
using System;
class Program
{
static void Main()
{
string result = StringTool.Truncate("Carrot", 3);
string result2 = StringTool.Truncate2("Carrot", 3);
Console.WriteLine(result);
Console.WriteLine(result2);
result = StringTool.Truncate("Computer", 20);
result2 = StringTool.Truncate2("Computer", 20);
Console.WriteLine(result);
Console.WriteLine(result2);
}
}
/// <summary>
/// Custom string utility methods.
/// </summary>
public static class StringTool
{
/// <summary>
/// Get a substring of the first N characters.
/// </summary>
public static string Truncate(string source, int length)
{
if (source.Length > length)
{
source = source.Substring(0, length);
}
return source;
}
/// <summary>
/// Get a substring of the first N characters. [Slow]
/// </summary>
public static string Truncate2(string source, int length)
{
return source.Substring(0, Math.Min(length, source.Length));
}
}Car
Car
Computer
Computer
Performance. I wanted to know if avoiding Substring() when it is not needed would have an impact on performance. And I found using the if-statement before calling Substring is faster.
Version 2 This code always uses substring, but uses Math.Min to ensure we do not take a substring that is too long.
Result Truncate, which avoids calling Substring(), is faster. It avoids a string method call in the benchmark.
C# program that benchmarks Truncate, Truncate2
using System;
using System.Diagnostics;
class Program
{
public static class StringTool
{
public static string Truncate(string source, int length)
{
if (source.Length > length)
{
source = source.Substring(0, length);
}
return source;
}
public static string Truncate2(string source, int length)
{
return source.Substring(0, Math.Min(length, source.Length));
}
}
const int _max = 100000000;
static void Main()
{
var s1 = Stopwatch.StartNew();
// Version 1: use Truncate.for (int i = 0; i < _max; i++)
{
string a = StringTool.Truncate("Carrot", 3);
string b = StringTool.Truncate("Carrot", 10);
}
s1.Stop();
// Version 2: use Truncate2.
var s2 = Stopwatch.StartNew();
for (int i = 0; i < _max; i++)
{
string a = StringTool.Truncate2("Carrot", 3);
string b = StringTool.Truncate2("Carrot", 10);
}
s2.Stop();
Console.WriteLine(((double)(s1.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
Console.WriteLine(((double)(s2.Elapsed.TotalMilliseconds * 1000000) / _max).ToString("0.00 ns"));
}
}14.18 ns Truncate
15.28 ns Truncate2
A summary. Here we saw 2 implementations of string Truncate. We validated that they have correct results. Avoiding the Substring call when it is not necessary is faster.
