我试图找到字符串中的句点数 [英] I am trying to find the number of periods in a string

问题描述

我试图找到一个字符串中的句点数（。）

我应该得到140当我应该只得到2.

我不明白原因。

我猜它不能用特殊字符工作但是用字母工作。



我尝试了什么：

 string period =。; 
正则表达式searchFor =新正则表达式（期间）; 
 int numOfPeriod = searchFor.Matches（SBDuties）.Count; 
 Response.Write（句号+< br />）; 
 
 Response.Write（句号数+ numOfPeriod +< br />）; 
 Response.Write（SBDuties）; 
 

解决方案

Quote：

我试图在字符串中找到句点数（。）

你正在使用RegEx，碰巧有些字符在RegEx中有特殊含义，你很幸运，因为' 。'是一个匹配任何字符的特殊字符。



正则表达式是一个功能强大的工具，但与任何工具一样，你需要学习如何使用它。 />


只是一些有趣的链接，可以帮助构建和调试RegEx。

以下是RegEx文档的链接：

perlre - perldoc.perl.org [ ^ ]

以下是帮助构建RegEx并调试它们的工具的链接：

.NET正则表达式测试程序 - 正则表达式风暴 [ ^ ]

Expresso正则表达式工具 [ ^ ]

这个显示RegEx是一个不错的图表对于了解RegEx的作用非常有用：

Debuggex：在线可视正则表达式测试器。 JavaScript，Python和PCRE。 [ ^ ]

除了RegEx之外还有其他选项可以很好地运行。请参阅 c＃ - 您如何计算a的出现次数？字符串中的字符串？ - 堆栈溢出 [ ^ ]有几个不错的选择。

 string period =[。]; 

I am trying to find the number of periods(.) in a string

I am getting 140 when I should when I should only get 2.
I do not understand the reason why.
I guessing it don't work with special characters but work with letters.

What I have tried:

string period = ".";
               Regex searchFor = new Regex(period);
               int numOfPeriod = searchFor.Matches(SBDuties).Count;
               Response.Write(period +"<br/>");

               Response.Write("Number of full stops " + numOfPeriod +"<br/>");
               Response.Write(SBDuties);

解决方案

Quote:

I am trying to find the number of periods(.) in a string

You are using RegEx, it happen that some chars have a special meaning in RegEx, and you are lucky because '.' is a special char that match any char.

Regex is a powerful tool, but like with any tool, you need to learn how to use it.

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

There are other options besides RegEx that perform very well. See c# - How would you count occurrences of a string within a string? - Stack Overflow[^] for several good alternatives.

string period = "[.]";

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