字符串中整数的出现 [英] Occurences for integer in string

问题描述

 package RegularEspressions; 
 
 import java.util.regex。*; 
 
公共类RegFndMultiple {
 public static void main（String args []）{
 Pattern pat = Pattern.compile（^（[+  - ]？[0-9] ] \\d * | 0）$）; 
 Matcher mat = pat.matcher（word 1 2 3 android）; 
 
 while（mat.find（））{
 System.out.println（在索引处找到的数字+ 
 mat.start（））; 
} 
} 
} 

应显示数字位置，代码打印整数位置



我尝试了什么：



更改了代码并添加了新模式

解决方案

）;
Matcher mat = pat.matcher（word 1 2 3 android）;

while（mat.find（））{
System.out.println（在索引处找到的数字+
mat.start（））;
}
}
}

应该显示数字的位置，打印整数位置的代码



我尝试了什么：



改变了代码并添加了新模式

你的模式是错误的，它只会匹配包含整数的行，而不是因为 ^ 和

。

模式会更好

< pre lang =text>（[+ - ]？[0-9] \\d * | 0）

在任何情况下，模式都过于复杂，我会使用

（[+  - ] ？\\\\ +）

只是一些有趣的链接来帮助构建和调试RegEx。

以下是RegEx文档的链接：

perlre - perldoc.perl.org [< a href =http://perldoc.perl.org/perlre.htmltarget =_ blanktitle =New Window> ^ ]

这是指向工具的链接帮助构建RegEx并调试它们：

.NET Regex Tester - Regex Storm [ ^ ]

Expresso正则表达式工具 [ ^ ]

RegExr：Learn，Build，&测试RegEx [ ^ ]

此节目RegEx是一个很好的图表，它非常有助于理解RegEx的作用：

Debuggex：在线可视正则表达式测试器。 JavaScript，Python和PCRE。 [ ^ ]



[更新]

尝试我的模式和你的解决方案测试1 23 -45测试

你可能会感到惊讶

package RegularEspressions;

import java.util.regex.*; 
 
public class RegFndMultiple { 
  public static void main(String args[]) { 
    Pattern pat = Pattern.compile("^([+-]?[0-9]\\d*|0)$"); 
    Matcher mat = pat.matcher("word 1 2 3 android"); 
 
    while(mat.find()) { 
      System.out.println("numbers found at index " + 
                         mat.start()); 
    } 
  } 
}

should display position of numbers , code that prints the position of integers

What I have tried:

changed code and added new patterns

解决方案

"); Matcher mat = pat.matcher("word 1 2 3 android"); while(mat.find()) { System.out.println("numbers found at index " + mat.start()); } } }

should display position of numbers , code that prints the position of integers

What I have tried:

changed code and added new patterns

Your pattern is wrong, it will match only lines containing an integer and nothing else because of ^ and

.
Pattern would be better as

"([+-]?[0-9]\\d*|0)"

In any cases, the pattern is over complicated, I would use

"([+-]?\\d+)"

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
RegExr: Learn, Build, & Test RegEx[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

[Update]
Try my pattern and your solution with "test 1 23 -45 test"
You may get surprised.

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