blocks|key|200575|text|下面是替换字符串最后一个匹配项的函数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|200576|public+static+string+ReplaceLastOccurrence(string+Source,+string+Find,+string+Replace)
{
++++++++int+place+=+Source.LastIndexOf(Find);

++++++++if(place+==+-1)
+++++++++++return+Source;

++++++++string+result+=+Source.Remove(place,+Find.Length).Insert(place,+Replace);
++++++++return+result;
}|code-block|syntax|javascript|200577|200578|Source是要对其执行操作的字符串，operation.|unordered-list-item|offset|length|style|CODE|200579|Find是要替换的字符串。|200580|Replace是要用来替换它的字符串。|200581|200582|entityMap^0|0|0|0|0|6|0|0|4|0|0|7|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Y|8|@$K|Z|L|10|M|N]]|9|@]|A|$]]|$1|O|3|P|5|J|7|11|8|@$K|12|L|13|M|N]]|9|@]|A|$]]|$1|Q|3|R|5|J|7|14|8|@$K|15|L|16|M|N]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|U|$]]

Here is the function to replace the last occurrence of a string

<pre><code>public static string ReplaceLastOccurrence(string Source, string Find, string Replace)
{
 int place = Source.LastIndexOf(Find);

 if(place == -1)
 return Source;

 string result = Source.Remove(place, Find.Length).Insert(place, Replace);
 return result;
}
</code></pre>

<ul>
<li><code>Source</code> is the string on which you want to do the operation.</li>
<li><code>Find</code> is the string that you want to replace. </li>
<li><code>Replace</code> is the string that you want to replace it with.</li>
</ul>

blocks|key|2826900|text|使用string.LastIndexOf()查找字符串最后一次出现的索引，然后使用子字符串查找解决方案。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2826901|entityMap^0|2|K|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Use <code>string.LastIndexOf()</code> to find the index of the last occurrence of the string and then use substring to look for your solution.

blocks|key|198773|text|您必须手动执行替换：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|198774|int+i+=+filePath.LastIndexOf(TnaName);
if+(i+>=+0)
++++filePath+=+filePath.Substring(0,+i)+%2B+filePath.Substring(i+%2B+TnaName.Length);|code-block|syntax|javascript|198775|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You have to do the replace manually:

<pre><code>int i = filePath.LastIndexOf(TnaName);
if (i &gt;= 0)
 filePath = filePath.Substring(0, i) + filePath.Substring(i + TnaName.Length);
</code></pre>

blocks|key|200596|text|我不明白为什么不能使用正则表达式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|200597|public+static+string+RegexReplace(this+string+source,+string+pattern,+string+replacement)
{
++return+Regex.Replace(source,pattern,+replacement);
}

public+static+string+ReplaceEnd(this+string+source,+string+value,+string+replacement)
{
++return+RegexReplace(source,+$"{value}$",+replacement);
}

public+static+string+RemoveEnd(this+string+source,+string+value)
{
++return+ReplaceEnd(source,+value,+string.Empty);
}|code-block|syntax|javascript|200598|用法：|200599|string+filePath+="F:/feb11/MFrame/Templates/feb11";
filePath+=+filePath.RemoveEnd("feb11");+//+F:/feb11/MFrame/Templates/
filePath+=+filePath.ReplaceEnd("feb11","jan11");+//+F:/feb11/MFrame/Templates/jan11|200600|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I don't see why Regex can't be used:

<pre class="lang-cs prettyprint-override"><code>public static string RegexReplace(this string source, string pattern, string replacement)
{
 return Regex.Replace(source,pattern, replacement);
}

public static string ReplaceEnd(this string source, string value, string replacement)
{
 return RegexReplace(source, $"{value}$", replacement);
}

public static string RemoveEnd(this string source, string value)
{
 return ReplaceEnd(source, value, string.Empty);
}
</code></pre>

Usage:

<pre class="lang-cs prettyprint-override"><code>string filePath ="F:/feb11/MFrame/Templates/feb11";
filePath = filePath.RemoveEnd("feb11"); // F:/feb11/MFrame/Templates/
filePath = filePath.ReplaceEnd("feb11","jan11"); // F:/feb11/MFrame/Templates/jan11
</code></pre>

blocks|key|3039858|text|只需一行代码即可实现更简单的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3039859|+static+string+ReplaceLastOccurrence(string+str,+string+toReplace,+string+replacement)
++++{
++++++++return+Regex.Replace(str,+$@"%5E(.*){Regex.Escape(toReplace)}(.*?)$",+$"$1{Regex.Escape(replacement)}$2");
++++}|code-block|syntax|javascript|3039860|因此，我们利用了正则表达式星号运算符的贪婪。该函数的用法如下：|3039861|var+s+=+"F:/feb11/MFrame/Templates/feb11";
var+tnaName+=+"feb11";
var+r+=+ReplaceLastOccurrence(s,tnaName,+string.Empty);|3039862|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The solution can be implemented even more simple with a single line:
<pre><code> static string ReplaceLastOccurrence(string str, string toReplace, string replacement)
 {
 return Regex.Replace(str, $@&quot;^(.*){Regex.Escape(toReplace)}(.*?)$&quot;, $&quot;$1{Regex.Escape(replacement)}$2&quot;);
 }
</code></pre>
Hereby we take advantage of the greediness of the regex asterisk operator. The function is used like this:
<pre><code>var s = &quot;F:/feb11/MFrame/Templates/feb11&quot;;
var tnaName = &quot;feb11&quot;;
var r = ReplaceLastOccurrence(s,tnaName, string.Empty);
</code></pre>

blocks|key|2826978|text|您可以使用System.IO名称空间中的Path类：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2826979|string+filePath+=+"F:/jan11/MFrame/Templates/feb11";

Console.WriteLine(System.IO.Path.GetDirectoryName(filePath));|code-block|syntax|javascript|2826980|entityMap^0|5|9|K|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

You can use a <code>Path</code> class from <code>System.IO</code> namepace:

<pre><code>string filePath = "F:/jan11/MFrame/Templates/feb11";

Console.WriteLine(System.IO.Path.GetDirectoryName(filePath));
</code></pre>

blocks|key|198833|text|以下代码不会替换路径/字符串中的TnaName，而是返回不包含TnaName的路径/字符串：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|198834|var+lastIndex+=+filePath.LastIndexOf(TnaName);+//+get+position+of+TnaName

filePath+=+filePath.Substring(0,+lastIndex);+//+get+path+till+position+of+TnaName|code-block|syntax|javascript|198835|entityMap^0|G|7|V|7|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

The following doesn't replace <code>TnaName</code> in the path/string, but instead returns it without <code>TnaName</code> included:
<pre><code>var lastIndex = filePath.LastIndexOf(TnaName); // get position of TnaName

filePath = filePath.Substring(0, lastIndex); // get path till position of TnaName
</code></pre>

blocks|key|198841|text|下面的函数拆分最后出现模式(要替换的单词)的字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|198842|然后，它使用替换字符串(在字符串的后半部分)更改模式。|198843|最后，它再次将字符串的两个部分连接在一起。|198844|using+System.Text.RegularExpressions;

public+string+ReplaceLastOccurance(string+source,+string+pattern,+string+replacement)
{
+++int+splitStartIndex+=+source.LastIndexOf(pattern,+StringComparison.OrdinalIgnoreCase);
+++string+firstHalf+=+source.Substring(0,+splitStartIndex);
+++string+secondHalf+=+source.Substring(splitStartIndex,+source.Length+-+splitStartIndex);
+++secondHalf+=+Regex.Replace(secondHalf,+pattern,+replacement,+RegexOptions.IgnoreCase);

+++return+firstHalf+%2B+secondHalf;
}|code-block|syntax|javascript|198845|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The following function splits a string where the pattern (word to be replaced) last occurs. 
Then it changes the pattern with the replacement string (in the second half of the string). 
Finally, it concatenates both string halves back with each other again.
<pre><code>using System.Text.RegularExpressions;

public string ReplaceLastOccurance(string source, string pattern, string replacement)
{
 int splitStartIndex = source.LastIndexOf(pattern, StringComparison.OrdinalIgnoreCase);
 string firstHalf = source.Substring(0, splitStartIndex);
 string secondHalf = source.Substring(splitStartIndex, source.Length - splitStartIndex);
 secondHalf = Regex.Replace(secondHalf, pattern, replacement, RegexOptions.IgnoreCase);

 return firstHalf + secondHalf;
}
</code></pre>

I have a problem where I need to replace the last occurrence of a word in a string.

Situation: I am given a string which is in this format:

<pre><code>string filePath ="F:/jan11/MFrame/Templates/feb11";
</code></pre>

I then replace <code>TnaName</code> like this:

<pre><code>filePath = filePath.Replace(TnaName, ""); // feb11 is TnaName
</code></pre>

This works, but I have a problem when <code>TnaName</code> is the same as my <code>folder name</code>. When this happens I end up getting a string like this:

<pre><code>F:/feb11/MFrame/Templates/feb11
</code></pre>

Now it has replaced both occurrences of <code>TnaName</code> with <code>feb11</code>. Is there a way that I can replace only the last occurrence of the word in my string?

Note: <code>feb11</code> is <code>TnaName</code> which comes from another process - that's not a problem.

Replace the last occurrence of a word in a string - C#

我有一个问题，我需要替换字符串中最后一个出现的单词。情况：我得到了一个字符串，其格式如下：string filePath ="F:/jan11/MFrame/Templates/feb11";然后，我像这样替换TnaName：filePath = filePath.Replace(TnaName, ""); // feb11 is TnaName这是可行的，但当TnaName与我的folder n

问替换字符串中最后一次出现的单词- C#
EN

回答 8

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问替换字符串中最后一次出现的单词- C#EN

回答 8

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问替换字符串中最后一次出现的单词- C#
EN