如何替换字符串的子串[重复]

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这个问题在这里已有答案：

String not replacing characters 5 answers
字符串不替换字符5的答案

Assuming I have a String string like this:

假设我有一个像这样的字符串字符串：

"abcd=0; efgh=1"

and I want to replace "abcd" by "dddd". I have tried to do such thing:

我想用“dddd”替换“abcd”。我试过做这样的事情：

string.replaceAll("abcd","dddd");

It does not work. Any suggestions?

这是行不通的。有什么建议么？

EDIT: To be more specific, I am working in Java and I am trying to parse the HTML document, concretely the content between <script> tags. I have already found a way how to parse this content into a string:

编辑：更具体地说，我在Java工作，我正在尝试解析HTML文档，具体是

 if(tag instanceof ScriptTag){
        if(((ScriptTag) tag).getStringText().contains("DataVideo")){
            String tagText = ((ScriptTag)tag).getStringText();
      }
}

Now I have to find a way how to replace one substring by another one.

现在我必须找到一种方法如何用另一个子串替换一个子串。

7 个解决方案

#1

You need to use return value of replaceAll() method. replaceAll() does not replace the characters in the current string, it returns a new string with replacement.

您需要使用replaceAll（）方法的返回值。 replaceAll（）不替换当前字符串中的字符，它返回带有替换的新字符串。

String objects are immutable, their values cannot be changed after they are created.

字符串对象是不可变的，它们的值在创建后无法更改。

You may use replace() instead of replaceAll() if you don't need regex.

如果不需要正则表达式，可以使用replace（）而不是replaceAll（）。

    String str = "abcd=0; efgh=1";
    String replacedStr = str.replaceAll("abcd", "dddd");

    System.out.println(str);
    System.out.println(replacedStr);

outputs

输出

abcd=0; efgh=1
dddd=0; efgh=1

#2

2 things you should note:

你应该注意的两件事：

Strings in Java are immutable to so you need to store return value of thereplace method call in another String.
Java中的字符串是不可变的，因此您需要将whereplace方法调用的返回值存储在另一个String中。
You don't really need a regex here, just a simple call to String#replace(String) will do the job.
你真的不需要这里的正则表达式，只需简单调用String＃replace（String）就可以了。

So just use this code:

所以只需使用此代码：

String replaced = string.replace("abcd", "dddd");

#3

You need to create the variable to assign the new value to, like this:

您需要创建变量以将新值分配给，如下所示：

String str = string.replaceAll("abcd","dddd");

#4

By regex i think this is java, the method replaceAll() returns a new String with the substrings replaced, so try this:

通过正则表达式我认为这是java，方法replaceAll（）返回一个替换了子字符串的新String，所以试试这个：

String teste = "abcd=0; efgh=1";

String teste2 = teste.replaceAll("abcd", "dddd");

System.out.println(teste2);

Output:

输出：

dddd=0; efgh=1

#5

Note that backslashes (\) and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see Matcher.replaceAll. Use java.util.regex.Matcher.quoteReplacement to suppress the special meaning of these characters, if desired.

请注意，替换字符串中的反斜杠（\）和美元符号（$）可能会导致结果与将其视为文字替换字符串时的结果不同;见Matcher.replaceAll。如果需要，请使用java.util.regex.Matcher.quoteReplacement来抑制这些字符的特殊含义。

from javadoc.

来自javadoc。

#6

In javascript:

在javascript中：

var str = "abcdaaaaaabcdaabbccddabcd";
document.write(str.replace(/(abcd)/g,"----"));
//example output: ----aaaaa----aabbccdd----

In other languages, it would be something similar. Remember to enable global matches.

在其他语言中，它将是类似的东西。请记住启用全局匹配。

#7

You are probably not assigning it after doing the replacement or replacing the wrong thing. Try :

在更换或更换错误的东西后，您可能没有分配它。试试：

String haystack = "abcd=0; efgh=1";
String result = haystack.replaceAll("abcd","dddd");

#1