blocks|key|1607887|text|str.replaceAll("\\%5E([0-9]%2B)",+"$1");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1607888|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>str.replaceAll("\\^([0-9]+)", "&lt;sup&gt;$1&lt;/sup&gt;");
</code></pre>

blocks|key|1607951|text|您将需要研究正则表达式中的捕获，以处理%5E3中的3。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1607952|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You'll want to look into capturing in regex to handle wrapping the 3 in ^3.

blocks|key|1607973|text|import+java.util.regex.PatternSyntaxException;

//+(:?\d%2B)+\*+x\%5E(:?\d%2B)
//+
//+Options:+%5E+and+$+match+at+line+breaks
//+
//+Match+the+regular+expression+below+and+capture+its+match+into+backreference+number+1+«(:?\d%2B)»
//++++Match+the+character+“:”+literally+«:?»
//+++++++Between+zero+and+one+times,+as+many+times+as+possible,+giving+back+as+needed+(greedy)+«?»
//++++Match+a+single+digit+0..9+«\d%2B»
//+++++++Between+one+and+unlimited+times,+as+many+times+as+possible,+giving+back+as+needed+(greedy)+«%2B»
//+Match+the+character+“+”+literally+«+»
//+Match+the+character+“*”+literally+«\*»
//+Match+the+characters+“+x”+literally+«+x»
//+Match+the+character+“%5E”+literally+«\%5E»
//+Match+the+regular+expression+below+and+capture+its+match+into+backreference+number+2+«(:?\d%2B)»
//++++Match+the+character+“:”+literally+«:?»
//+++++++Between+zero+and+one+times,+as+many+times+as+possible,+giving+back+as+needed+(greedy)+«?»
//++++Match+a+single+digit+0..9+«\d%2B»
//+++++++Between+one+and+unlimited+times,+as+many+times+as+possible,+giving+back+as+needed+(greedy)+«%2B»
try+{
++++String+resultString+=+subjectString.replaceAll("(?m)(:?\\d%2B)+\\*+x\\%5E(:?\\d%2B)",+"$1x$2");
}+catch+(PatternSyntaxException+ex)+{
++++//+Syntax+error+in+the+regular+expression
}+catch+(IllegalArgumentException+ex)+{
++++//+Syntax+error+in+the+replacement+text+(unescaped+$+signs?)
}+catch+(IndexOutOfBoundsException+ex)+{
++++//+Non-existent+backreference+used+the+replacement+text
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1607974|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>import java.util.regex.PatternSyntaxException;

// (:?\d+) \* x\^(:?\d+)
// 
// Options: ^ and $ match at line breaks
// 
// Match the regular expression below and capture its match into backreference number 1 «(:?\d+)»
// Match the character “:” literally «:?»
// Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
// Match a single digit 0..9 «\d+»
// Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
// Match the character “ ” literally « »
// Match the character “*” literally «\*»
// Match the characters “ x” literally « x»
// Match the character “^” literally «\^»
// Match the regular expression below and capture its match into backreference number 2 «(:?\d+)»
// Match the character “:” literally «:?»
// Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
// Match a single digit 0..9 «\d+»
// Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
try {
 String resultString = subjectString.replaceAll("(?m)(:?\\d+) \\* x\\^(:?\\d+)", "$1x&lt;sup&gt;$2&lt;/sup&gt;");
} catch (PatternSyntaxException ex) {
 // Syntax error in the regular expression
} catch (IllegalArgumentException ex) {
 // Syntax error in the replacement text (unescaped $ signs?)
} catch (IndexOutOfBoundsException ex) {
 // Non-existent backreference used the replacement text
}
</code></pre>

blocks|key|1608089|text|如果这是用于任何一般的数学表达式，并且允许使用括号表达式，那么使用正则表达式将非常困难(也许是不可能的)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1608090|如果唯一的替代品是您展示的那些，这并不难做到。首先剥离*的，然后像Can+Berk+Güder展示的那样使用捕获来处理%5E的。|offset|length|style|CODE|1608091|entityMap^0|0|R|1|1N|1|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

If this is for any general math expression and parenthetical expressions are allowed, it will be very difficult (perhaps impossible) to do this with regular expressions.

If the only replacements are the ones you showed, it's not that hard to do. First strip out <code>*</code>'s, then use capturing like Can Berk Güder showed to handle the <code>^</code>'s.

blocks|key|1608139|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1608140|String+str+=+"5+*+x%5E3+-+6+*+x%5E1+%2B+1";
String+replacedStr+=+str.replaceAll("\\%5E(\\d%2B)",+"\$1");|code-block|syntax|javascript|1608141|确保导入java.util.regex。|1608142|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try this:

<pre><code>String str = "5 * x^3 - 6 * x^1 + 1";
String replacedStr = str.replaceAll("\\^(\\d+)", "&lt;sup&gt;\$1&lt;/sup&gt;");
</code></pre>

Be sure to import java.util.regex.

blocks|key|1393321|text|你的多项式是什么？如果您正在“处理”它，我会设想在某个时刻生成某种类型的子表达式树，并且会认为使用它来生成字符串要比使用正则表达式重新解析原始表达式简单得多。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1393322|只是提出了一种不同的思考方式。我不确定你的应用中还发生了什么。|1393323|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

What is your polynomial? If you're "processing" it, I'm envisioning some sort of tree of sub-expressions being generated at some point, and would think that it would be much simpler to use that to generate your string than to re-parse the raw expression with a regex.

Just throwing a different way of thinking out there. I'm not sure what else is going on in your app.

blocks|key|1393340|text|String+input+=+"hello+I'm+a+java+dev"+%2B
"no+job+experience+needed"+%2B
"senior+software+engineer"+%2B
"java+job+available+for+senior+software+engineer";

String+fixedInput+=+input.replaceAll("(java%7Cjob%7Csenior)",+"$1");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1393341|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>String input = "hello I'm a java dev" +
"no job experience needed" +
"senior software engineer" +
"java job available for senior software engineer";

String fixedInput = input.replaceAll("(java|job|senior)", "&lt;b&gt;$1&lt;/b&gt;");
</code></pre>

blocks|key|1393355|text|class+Replacement+
{
++++public+static+void+main(String+args[])
++++{
++++++++String+Main+=+"5+*+x%5E3+-+6+*+x%5E1+%2B+1";
++++++++String+replaced+=+Main.replaceAll("(?m)(:?\\d%2B)+\\*+x\\%5E(:?\\d%2B)",+"$1x$2");
++++++++System.out.println(replaced);
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1393356|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>class Replacement 
{
 public static void main(String args[])
 {
 String Main = "5 * x^3 - 6 * x^1 + 1";
 String replaced = Main.replaceAll("(?m)(:?\\d+) \\* x\\^(:?\\d+)", "$1x&lt;sup&gt;$2&lt;/sup&gt;");
 System.out.println(replaced);
 }
}
</code></pre>

blocks|key|1608309|text|private+String+removeScript(String+content)+{
++++Pattern+p+=+Pattern.compile("<script[%5E>]*>(.*?)</script>",
++++++++++++Pattern.DOTALL+%7C+Pattern.CASE_INSENSITIVE);
++++return+p.matcher(content).replaceAll("");
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1608310|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>private String removeScript(String content) {
 Pattern p = Pattern.compile("&lt;script[^&gt;]*&gt;(.*?)&lt;/script&gt;",
 Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
 return p.matcher(content).replaceAll("");
}
</code></pre>

blocks|key|1393417|text|试试这个，可能不是最好的方法。但它是有效的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1393418|String+str+=+"5+*+x%5E3+-+6+*+x%5E1+%2B+1";
str+=+str.replaceAll("(?x)(\\d%2B)(\\s%2B?\\*?\\s%2B?)(\\w%2B?)(\\%5E%2B?)(\\d%2B?)",+"$1$3$5");
System.out.println(str);|code-block|syntax|javascript|1393419|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|$]]

Try this, may not be the best way. but it works

<pre><code>String str = "5 * x^3 - 6 * x^1 + 1";
str = str.replaceAll("(?x)(\\d+)(\\s+?\\*?\\s+?)(\\w+?)(\\^+?)(\\d+?)", "$1$3&lt;sup&gt;$5&lt;/sup&gt;");
System.out.println(str);
</code></pre>

blocks|key|1393470|text|看看antlr4吧。与仅使用正则表达式相比，它将使您在创建树结构方面走得更远。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1393471|https://github.com/antlr/grammars-v4/tree/master/calculator+(calculator.g4包含您需要的语法)|offset|length|1393472|简而言之，您定义了解析表达式的语法，使用antlr生成java代码，并在构建树时添加回调来处理计算。|1393473|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/antlr/grammars-v4/tree/master/calculator^0|0|0|1N|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

Take a look at antlr4. It will get you much farther along in creating a tree structure than regular expressions alone.

<a href="https://github.com/antlr/grammars-v4/tree/master/calculator" rel="nofollow">https://github.com/antlr/grammars-v4/tree/master/calculator</a> (calculator.g4 contains the grammar you need)

In a nutshell, you define the grammar to parse an expression, use antlr to generate java code, and add callbacks to handle evaluation when the tree is being built.

blocks|key|1393532|text|"5+*+x%5E3+-+6+*+x%5E1+%2B+1".replaceAll("\\W*\\*\\W*","").replaceAll("\\%5E(\\d%2B)","$1");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1393533|请注意，将两个替换项合并到一个正则表达式/替换项中将是一个糟糕的选择，因为更通用的表达式(如x%5E3+-+6+*+x+)将失败。|unstyled|offset|length|style|CODE|1393534|entityMap^0|0|1A|B|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>"5 * x^3 - 6 * x^1 + 1".replaceAll("\\W*\\*\\W*","").replaceAll("\\^(\\d+)","&lt;sup&gt;$1&lt;/sup&gt;");
</code></pre>

please note that joining both replacements in a single regex/replacement would be a bad choice because more general expressions such as <code>x^3 - 6 * x</code> would fail.

As part of a project for school, I need to replace a string from the form:

<pre><code>5 * x^3 - 6 * x^1 + 1
</code></pre>

to something like:

<pre><code>5x&lt;sup&gt;3&lt;/sup&gt; - 6x&lt;sup&gt;1&lt;/sup&gt; + 1
</code></pre>

I believe this can be done with regular expressions, but I don't know how to do it yet.

Can you lend me a hand? 

P.S. The actual assignment is to implement a Polynomial Processing Java application, and I'm using this to pass polynomial.toString() from the model to the view, and I want do display it using html tags in a pretty way.

Java; String replace (using regular expressions)?

Java

作为学校项目的一部分，我需要替换表单中的字符串：5 * x^3 - 6 * x^1 + 1类似这样的东西：5x3 - 6x1 + 1我相信用正则表达式可以做到这一点，但我还不知道怎么做。你能帮我一下吗？附注:实际的任务是实现一个多项式处理的Java应用程序，我用它将polyn...

问Java；字符串替换(使用正则表达式)？
EN

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Java；字符串替换(使用正则表达式)？EN

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Java；字符串替换(使用正则表达式)？
EN