blocks|key|1107733|text|您可以使用正则表达式和删除非数字。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1107734|str+=+str.replaceAll("\\D%2B","");|code-block|syntax|javascript|1107735|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 can use regex and delete non-digits.

<pre><code>str = str.replaceAll("\\D+","");
</code></pre>

blocks|key|1107747|text|public+String+extractDigits(String+src)+{
++++StringBuilder+builder+=+new+StringBuilder();
++++for+(int+i+=+0;+i+<+src.length();+i%2B%2B)+{
++++++++char+c+=+src.charAt(i);
++++++++if+(Character.isDigit(c))+{
++++++++++++builder.append(c);
++++++++}
++++}
++++return+builder.toString();
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1107748|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>public String extractDigits(String src) {
 StringBuilder builder = new StringBuilder();
 for (int i = 0; i &lt; src.length(); i++) {
 char c = src.charAt(i);
 if (Character.isDigit(c)) {
 builder.append(c);
 }
 }
 return builder.toString();
}
</code></pre>

blocks|key|1107890|text|input.replaceAll("[%5E0-9?!\\.]","")|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1107891|这将忽略小数点。|unstyled|1107892|例如:如果你有一个445.3kg作为输入，输出将是445.3。|offset|length|style|CODE|1107893|entityMap^0|0|0|9|7|P|5|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|P|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|N|$]]

<pre><code>input.replaceAll("[^0-9?!\\.]","")
</code></pre>

This will ignore the decimal points.

eg: if you have an input as <code>445.3kg</code> the output will be <code>445.3</code>.

blocks|key|1107815|text|使用Google+Guava：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1107816|CharMatcher.DIGIT.retainFrom("123-456-789");|code-block|syntax|javascript|1107817|CharMatcher是可插拔的，并且使用起来非常有趣，例如，您可以执行以下操作：|1107818|String+input+=+"My+phone+number+is+123-456-789!";
String+output+=+CharMatcher.is('-').or(CharMatcher.DIGIT).retainFrom(input);|1107819|output+==+123-456-789|1107820|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Using Google Guava:

<pre><code>CharMatcher.DIGIT.retainFrom("123-456-789");
</code></pre>

CharMatcher is plug-able and quite interesting to use, for instance you can do the following:

<pre><code>String input = "My phone number is 123-456-789!";
String output = CharMatcher.is('-').or(CharMatcher.DIGIT).retainFrom(input);
</code></pre>

output == 123-456-789

blocks|key|892894|text|使用正则表达式来匹配您的需求。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892895|String+num,num1,num2;
String+str+=+"123-456-789";
String+regex+="(\\d%2B)";
Matcher+matcher+=+Pattern.compile(+regex+).matcher(+str);
while+(matcher.find(+))
{
num+=+matcher.group();+++++
System.out.print(num);+++++++++++++++++
}|code-block|syntax|javascript|892896|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|$]]

Use regular expression to match your requirement.

<pre><code>String num,num1,num2;
String str = "123-456-789";
String regex ="(\\d+)";
Matcher matcher = Pattern.compile( regex ).matcher( str);
while (matcher.find( ))
{
num = matcher.group(); 
System.out.print(num); 
}
</code></pre>

blocks|key|892947|text|您可以使用str.replaceAll("[%5E0-9]",+"");|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|892948|entityMap^0|5|T|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|$]]

You can use <code>str.replaceAll("[^0-9]", "");</code>

blocks|key|1107980|text|使用Kotlin和Lambda表达式，您可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1107981|val+digitStr+=+str.filter+{+it.isDigit()+}|code-block|syntax|javascript|1107982|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|$]]

Using Kotlin and Lambda expressions you can do it like this:
<pre><code>val digitStr = str.filter { it.isDigit() }
</code></pre>

blocks|key|1107932|text|我已经确定了电话号码%2B9+(987)+124124的代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1107933|Unicode字符占用4个字节。|1107934|public+static+String+stripNonDigitsV2(+CharSequence+input+)+{
++++if+(input+==+null)
++++++++return+null;
++++if+(+input.length()+==+0+)
++++++++return+"";

++++char[]+result+=+new+char[input.length()];
++++int+cursor+=+0;
++++CharBuffer+buffer+=+CharBuffer.wrap(+input+);
++++int+i=0;
++++while+(+i<+buffer.length()++)+{+//buffer.hasRemaining()
++++++++char+chr+=+buffer.get(i);
++++++++if+(chr=='u'){
++++++++++++i=i%2B5;
++++++++++++chr=buffer.get(i);
++++++++}

++++++++if+(+chr+>+39+&&+chr+<+58+)
++++++++++++result[cursor%2B%2B]+=+chr;
++++++++i=i%2B1;
++++}

++++return+new+String(+result,+0,+cursor+);
}|code-block|syntax|javascript|1107935|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I have finalized the code for phone numbers +9 (987) 124124.

Unicode characters occupy 4 bytes.

<pre><code>public static String stripNonDigitsV2( CharSequence input ) {
 if (input == null)
 return null;
 if ( input.length() == 0 )
 return "";

 char[] result = new char[input.length()];
 int cursor = 0;
 CharBuffer buffer = CharBuffer.wrap( input );
 int i=0;
 while ( i&lt; buffer.length() ) { //buffer.hasRemaining()
 char chr = buffer.get(i);
 if (chr=='u'){
 i=i+5;
 chr=buffer.get(i);
 }

 if ( chr &gt; 39 &amp;&amp; chr &lt; 58 )
 result[cursor++] = chr;
 i=i+1;
 }

 return new String( result, 0, cursor );
}
</code></pre>

blocks|key|892992|text|import+java.util.*;
public+class+FindDigits{

+public+static+void+main(String+[]args){
++++FindDigits+h=new++FindDigits();
++++h.checkStringIsNumerical();
+}

+void+checkStringIsNumerical(){
++++String+h="hello+123+for+the+rest+of+the+98475wt355";
+++++for(int+i=0;i<h.length();i%2B%2B)++{
++++++if(h.charAt(i)!='+'){
+++++++System.out.println("Is+this+'"%2Bh.charAt(i)%2B"'+is+a+digit?:"%2BCharacter.isDigit(h.charAt(i)));
+++++++}
++++}
+}

void+checkStringIsNumerical2(){
++++String+h="hello+123+for+2the+rest+of+the+98475wt355";
+++++for(int+i=0;i<h.length();i%2B%2B)++{
+++++++++char+chr=h.charAt(i);
++++++if(chr!='+'){
+++++++if(Character.isDigit(chr)){
++++++++++System.out.print(chr)+;
+++++++}
+++++++}
++++}
+}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|892993|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.*;
public class FindDigits{

 public static void main(String []args){
 FindDigits h=new FindDigits();
 h.checkStringIsNumerical();
 }

 void checkStringIsNumerical(){
 String h="hello 123 for the rest of the 98475wt355";
 for(int i=0;i&lt;h.length();i++) {
 if(h.charAt(i)!=' '){
 System.out.println("Is this '"+h.charAt(i)+"' is a digit?:"+Character.isDigit(h.charAt(i)));
 }
 }
 }

void checkStringIsNumerical2(){
 String h="hello 123 for 2the rest of the 98475wt355";
 for(int i=0;i&lt;h.length();i++) {
 char chr=h.charAt(i);
 if(chr!=' '){
 if(Character.isDigit(chr)){
 System.out.print(chr) ;
 }
 }
 }
 }
}
</code></pre>

I have a Java <code>String</code> object. I need to extract only digits from it. I'll give an example:

<code>"123-456-789"</code> I want <code>"123456789"</code>

Is there a library function that extracts only digits?

Thanks for the answers. Before I try these I need to know if I have to install any additional llibraries?

Extract digits from a string in Java

我有一个Java String对象。我只需要从其中提取数字。我举个例子："123-456-789"我想要"123456789"有没有只提取数字的库函数？谢谢你的回答。在我尝试这些之前，我需要知道我是否必须安装任何额外的llibraries？

问在Java中从字符串中提取数字
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