删除字符串末尾的数字C＃

Question

I'm trying to remove numbers in the end of a given string.

AB123 -> AB
123ABC79 -> 123ABC

I've tried something like this;

string input = "123ABC79";
string pattern = @"^\\d+|\\d+$";
string replacement = "";
Regex rgx = new Regex(pattern);
string result = rgx.Replace(input, replacement);

Yet the replacement string is same as the input. I'm not very familiar with regex. I can simply split the string into a character array, and loop over it to get it done, but it does not feel like a good solution. What is a good practice to remove numbers that are only in the end of a string?

Thanks in advance.

Answer 1

String.TrimEnd() is faster than using a regex:

var digits = new[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
var input = "123ABC79";
var result = input.TrimEnd(digits);

Benchmark app:

    string input = "123ABC79";
    string pattern = @"\d+$";
    string replacement = "";
    Regex rgx = new Regex(pattern);

    var iterations = 1000000;
    var sw = Stopwatch.StartNew();
    for (int i = 0; i < iterations; i++)
    {
        rgx.Replace(input, replacement);
    }

    sw.Stop();
    Console.WriteLine("regex:\t{0}", sw.ElapsedTicks);

    var digits = new[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
    sw.Restart();
    for (int i = 0; i < iterations; i++)
    {
        input.TrimEnd(digits);
    }

    sw.Stop();
    Console.WriteLine("trim:\t{0}", sw.ElapsedTicks);

Result:

regex:  40052843
trim:   2000635

Answer 2

Try this:

string input = "123ABC79";
string pattern = @"\d+$";
string replacement = "";
Regex rgx = new Regex(pattern);
string result = rgx.Replace(input, replacement);

Putting the $ at the end will restrict searches to numeric substrings at the end. Then, since we are calling Regex.Replace , we need to pass in the replacement pattern as the second parameter.

Demo

Answer 3

try this:

string input = "123ABC79";
string pattern = @".+\D+(?=\d+)";
Match match = Regex.Match(input, pattern);
string result = match.Value;

but you also can use a simple cycle:

string input = "123ABC79";
int i = input.Length - 1;
for (; i > 0 && char.IsDigit(input[i - 1]); i--)
{}
string result = input.Remove(i);

Answer 4

you can use this:

string strInput = textBox1.Text;
textBox2.Text = strInput.TrimEnd(new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' });

I got it from this post: Simple get string (ignore numbers at end) in C#

Answer 5

 (? <=[A-Za-z]*)\d*

应该解析它