Question

C#中如何搜索一个string中一共出现某个字符的次数？

比如要判断一篇文章中出现“red”的次数 如何实现？

Answer 1

这个需要靠编程,可以通过循环,每次搜索到一个red就加1.
给你参考代码:
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
label1.Text = string.Format("string count:{0}", GetCount(richTextBox1.Text));
}

private int GetCount(string str)
{
int cunt=0;
string[] strs = str.Split(new char[] { ' ' });
foreach(string tpStr in strs)
{
if(tpStr.ToLower().IndexOfAny(
new char[]{'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q',
'r','s','t','u','v','w','x','y','z'})>=0)
{
cunt++;
}
}
return cunt;
}

Answer 2

使用Regex类,指定一个正则表达式,
使用MatchCollection类 获取 Regex类实例的所有匹配,
:
string regexText = @"(red)";//需要匹配的字串
string inputs = "asdfredadfaredrearfredrererdreadfred" //目标文本;

MatchCollection mc = new Regex(regexText).Matches(inputs);

mc.Count //匹配数量.

Answer 3

下面这个count就是你要的结果
int i=0;
int count = 0;
string test = "redaabredjjkreddd";
while(test.IndexOf("red",i)>=0)
{
i = test.IndexOf("red",i) + 1;
count++;
}

Answer 4

string str="asdfnewsdafasdnewssdfnews";
string substr="red";
int count= str.Replace(substr,"|").Split('|').Length-1;