如果使用 C# 在字符串中找到特定关键字，则在特定关键字之前和之后插入空格答案

【问题标题】：Insert space before and after specific keywords if they are found in string using C#如果使用 C# 在字符串中找到特定关键字，则在特定关键字之前和之后插入空格
【发布时间】：2019-03-02 23:47:00
【问题描述】：

我有一个哑字符串

Today the auto industry is booming. Automated machines are big part of it and it's working great. They are doing very big autonomous work.

我希望能够提供一个关键字字典作为List<string>。

然后我想在我的文本中搜索这些关键字。如果找到关键字，请检查前后是否包含空格。如果是，什么也不做。如果不包含，则在之前或之后添加空格。所以关键字可以是一个单词的开头中间或结尾的一部分。所以基本上在文本中使关键字成为单个单词。

示例关键字：auto, work, the

为了我的文字

Today the auto industry is booming. Automated machines are big part of it and it's working great. They are doing very big autonomous work.

结果应该是：

Today the auto industry is booming. Auto mated machines are big part of it and it's work ing great. The y are doing very big auto nomous work .

【问题讨论】：

为什么不用正则表达式？这感觉是正则表达式的最佳时机......
我不太懂正则表达式……但当然没关系。
你可以搜索，我认为这是一个经典的正则表达式。见：stackoverflow.com/questions/5650909/…
因为它应该是一个单词
对于每个单词，将单词替换为" word "。然后将" word"（前面两个空格）替换为" word"，将"word "（末尾两个空格）替换为"word "，以处理双空格问题（即那里已经有空格）。

标签： c# split

【解决方案1】：

这是一种方法。它通过关键字逐个关键字进行比较，忽略大小写。如果找到关键字，则检查前后是否有空格并添加。

public static string AddSpacesAroundWords(string text, List<string> words)
{
    foreach(string word in words) {
        int index = 0;
        while(index < text.Length) {
            index = text.IndexOf(word, index, StringComparison.CurrentCultureIgnoreCase);
            if(index == -1) {
                // no occurrence of this word anymore
                break;
            }
            // check if there is a space at the beginning of the word
            if(index > 0 && text[index - 1] != ' ') {
                text = text.Insert(index++ - 1, " ");
            }
            // check if there is a space at the end of the word
            if(index + word.Length < text.Length && text[index + word.Length] != ' ') {
                text = text.Insert(index++ + word.Length, " ");
            }
            index += word.Length;
        }
    }
    return text;
}

用法：

string original = "Today the auto industry is booming. Automated machines are big part of it and it's working great. They are doing very big autonomous work.";
var words = new List<string> { "auto", "work", "the" };
string result = AddSpacesAroundWords(original, words);
// result is now "Today the auto industry is booming. Auto mated machines are big part of it and it's work ing great. The y are doing very big auto nomous work ."

【讨论】：

【解决方案2】：

这只是 GregaMohorko 答案的修改/变体，我赞成：

private void Form1_Load(object sender, EventArgs e)
{
    tbKeywords.Text = "auto, work, the";
    textBox1.Text = "Today the auto industry is booming. Automated machines are big part of it and it's working great. They are doing very big autonomous work.";
}

private void button1_Click(object sender, EventArgs e)
{
    textBox2.Text = AddSpaceAroundWords(textBox1.Text, tbKeywords.Text);        
}

private string AddSpaceAroundWords(string sentence, string CommaSeparatedKeyWords)
{
    int index;
    string keyword;
    foreach (string key in CommaSeparatedKeyWords.Split(",".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
    {
        index = 0;
        keyword = key.Trim();       
        while ((index = sentence.IndexOf(keyword, index, StringComparison.InvariantCultureIgnoreCase)) != -1)
        {
            if ((index > 0) && (sentence[index - 1] != ' '))
            {
                sentence = sentence.Insert(index++, " ");
            }
            if (((index + keyword.Length) < sentence.Length) && (sentence[index + keyword.Length] != ' ')) {
                sentence = sentence.Insert(index++ + keyword.Length, " ");
            }
            index += keyword.Length;
        }
    }
    return sentence;
}

【讨论】：