使用与string.replace匹配整个单词 [英] Use string.Replace to match whole words
问题描述
我使用.NET 2.0和WinForms。
目前,我需要一个代码与另一个在一个给定的文本替换字符串,但在它的文字应该只找全字。我的意思是:
字符串名称= @COUNTER = $ 40个
CLOCK_COUNTER = $ 60;
NAME = name.Replace(COUNTER,COUNT);
它应该只替换 COUNTER的第一个实例
与 COUNT
,因为这是整个单词。然而,似乎与string.replace
不采取整字考虑。
请不建议正则表达式。我已经试了一下,这是我的需要过于缓慢。我需要的东西非常快速和有效。我怎么能做到这一点?
字符串输入= @COUNTER = $ $ 40 b $ b CLOCK_COUNTER = $ 60;
字符串名称= Regex.Replace(输入,@\bCOUNTER\b,COUNT);
\b
标记词边界值。
要正则表达式的唯一选择是开发自己的算法!搜索COUNTER的测试不是一个单词字符前面和后面的字符。
修改
下面是我作为扩展方法解决方案:
公共静态类ReplaceWordNoRegex
{
私人静态布尔IsWordChar(焦三)
{
返回Char.IsLetterOrDigit(三)|| ç=='_';
}
公共静态字符串ReplaceFullWords(这个字符串s,串oldWord,串newWord)
{
如果(S == NULL){
返回空值;
}
INT的startIndex = 0;
,而(真){
INT位置= s.IndexOf(oldWord,则startIndex);
如果(位置== -1){
返回小号;
}
INT indexAfter =位置+ oldWord.Length;
如果((位置== 0 || IsWordChar(S [位置 - 1]))及!及(indexAfter == || s.Length IsWordChar(S [indexAfter]))){
S = s.Substring(0位)+ newWord + s.Substring(indexAfter);
的startIndex =位置+ newWord.Length;
}其他{
的startIndex =位置+ oldWord.Length;
}
}
}
}
编辑#2:
和这里是StringBuilder的一个解决方案。
公共静态字符串ReplaceFullWords(这个字符串s,串oldWord,串newWord)
{
如果(S == NULL){
返回NULL;
}
INT的startIndex = 0; //当我们开始以秒来搜索。
INT copyPos = 0; //当我们开始从s复制到某人。
变种某人=新的StringBuilder();
,而(真){
INT位置= s.IndexOf(oldWord,则startIndex);
如果(位置== -1){
如果(copyPos == 0){
返回小号;
}
如果(s.Length> copyPos){//复制最后一个大块。
sb.Append(s.Substring(copyPos,s.Length - copyPos));
}
返回sb.ToString();
}
INT indexAfter =位置+ oldWord.Length;
如果((位置== 0 || IsWordChar(S [位置 - 1]))及!及(indexAfter == || s.Length IsWordChar(S [indexAfter]))){
sb.Append(s.Substring(copyPos,位置 - copyPos))追加(newWord)。
copyPos =位置+ oldWord.Length;
}
的startIndex =位置+ oldWord.Length;
}
}
I'm using NET 2.0 and WinForms.
Currently, I need a code to replace a string with another one in a given text, but in the text it should only look for whole words. What I mean is:
string name = @"COUNTER = $40
CLOCK_COUNTER = $60";
name = name.Replace("COUNTER", "COUNT");
It should only replace the first instance of COUNTER
with COUNT
, because that's whole word. However, it seems string.Replace
does not take whole word into consideration.
Please don't recommend regex. I have already tried it, and it's too slow for my needs. I need something very fast and efficient. How could I accomplish this?
string input = @"COUNTER = $40
CLOCK_COUNTER = $60";
string name = Regex.Replace(input, @"\bCOUNTER\b", "COUNT");
\b
marks word boundries.
The only alternative to Regex is to develop your own algorithm! Search for "COUNTER" and test the previous and following character for not being a word character.
EDIT:
Here is my solution as extension method:
public static class ReplaceWordNoRegex
{
private static bool IsWordChar(char c)
{
return Char.IsLetterOrDigit(c) || c == '_';
}
public static string ReplaceFullWords(this string s, string oldWord, string newWord)
{
if (s == null) {
return null;
}
int startIndex = 0;
while (true) {
int position = s.IndexOf(oldWord, startIndex);
if (position == -1) {
return s;
}
int indexAfter = position + oldWord.Length;
if ((position == 0 || !IsWordChar(s[position - 1])) && (indexAfter == s.Length || !IsWordChar(s[indexAfter]))) {
s = s.Substring(0, position) + newWord + s.Substring(indexAfter);
startIndex = position + newWord.Length;
} else {
startIndex = position + oldWord.Length;
}
}
}
}
EDIT #2: And here is a solution with StringBuilder.
public static string ReplaceFullWords(this string s, string oldWord, string newWord)
{
if (s == null) {
return null;
}
int startIndex = 0; // Where we start to search in s.
int copyPos = 0; // Where we start to copy from s to sb.
var sb = new StringBuilder();
while (true) {
int position = s.IndexOf(oldWord, startIndex);
if (position == -1) {
if (copyPos == 0) {
return s;
}
if (s.Length > copyPos) { // Copy last chunk.
sb.Append(s.Substring(copyPos, s.Length - copyPos));
}
return sb.ToString();
}
int indexAfter = position + oldWord.Length;
if ((position == 0 || !IsWordChar(s[position - 1])) && (indexAfter == s.Length || !IsWordChar(s[indexAfter]))) {
sb.Append(s.Substring(copyPos, position - copyPos)).Append(newWord);
copyPos = position + oldWord.Length;
}
startIndex = position + oldWord.Length;
}
}
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