正则表达式匹配用多个逗号分隔的数字

Question

I'm working on identifying patterns using regex.

My use-case is to find strings of the following format

100,253,2586,3654

Here is what I've tried

(\d+\,+\d+\,*)+

but it doesn't seem to work properly.

Help me figure out the issue.

Further to comments:
pattern Should identify

1. Any combination of numbers separated by a comma  (eg: 123,465,798)  
2. shouldn't begin or end with comma (eg: ,123,46 )  
3. Decimals (eg: 123,465.2324)

Answer 1

Try something like this :

public static void main(String[] args) {
    String s = "100,253,2586,3654";
    System.out.println(s.matches("((?<!^,)\\d+(,(?!$)|$))+"));
}

Edit : Regex explanation.

((?<!^,)\\\\d+(,(?!$)|$))+") ==>

\\\\d+ ==> matches one or more digits.

(?<!^,) ==> Negative look-behind. Checks if String doesn't start with a ",".

(,(?!$)|$))+") ==> checks digits are - either followed by a comma and NOT followed by end of String OR followed by end of String.

This will

1. Prevent a comma at the beginning.
2. prevent comma at the end.
3. multiple commas

Answer 2

This should match the numerics you wish to grab. Note that it allows a trailing decimal point since you didn't specify anything about that consideration:

\d+(,\d+)*(\.\d*)?

Perhaps you need some lookaround to guarantee that matches are neither preceded nor followed by whatever characters you would have invalidate the match. But can't you have a period or comma as regular punctuation immediately after a number in a typical body of text?

Answer 3

^\d+(?:,\d+)*$

这应该做它you.Your正则表达式不会匹配只有123 。如果这不是一个可能的情况下使用

^\d+(?:,\d+)+$

Answer 4

use this regex:

[^\,](\d+\.?,?)+[^\,]$

This should apply to your given cases

Answer 5

I had trouble getting @TheLostMind's answer to work when I was trying to match the number within a string of other letters. I ended up going with:

 \d+(,\d+)*(\.\d+)?

(will need to escape those backslashes to use in your pattern string, ie \\\\d+(,\\\\d+)*(\\\\.\\\\d+)? )

Note : This doesn't quite answer the OP, as it doesn't check for no leading or trailing comma directly, but if the number does have that, it won't pull it from the CharSequence.

Explanation:

\\d+ matches one or many numbers

(,\\d+)* matches zero or more groups of "a comma followed by one or many numbers"

(\\.\\d+)? matches zero or one groups of a decimal point followed by one or many numbers

Pattern pattern = Pattern.compile("\\d+(,\\d+)*(\\.\\d+)?");
Matcher m1 = pattern.matcher("100,253,2586,3654");
Matcher m2 = pattern.matcher("100,253,2586,3654.999");
Matcher m3 = pattern.matcher("10,000,000,253,023,253,365,2536,2563,253");
Matcher m4 = pattern.matcher("10,000,456,258.99");
Matcher m5 = pattern.matcher("10.99");
Matcher m6 = pattern.matcher("1");
Matcher m7 = pattern.matcher("Text on the left 100,253,2586,3654.00000 text on the right");
Matcher m8 = pattern.matcher("Text on the left ,100,253,2586,3654.00000, text on the right");

System.out.println("Matcher 1 matches " + m1.find() + " result: " + m1.group());
System.out.println("Matcher 2 matches " + m2.find() + " result: " + m2.group());
System.out.println("Matcher 3 matches " + m3.find() + " result: " + m3.group());
System.out.println("Matcher 4 matches " + m4.find() + " result: " + m4.group());
System.out.println("Matcher 5 matches " + m5.find() + " result: " + m5.group());
System.out.println("Matcher 6 matches " + m6.find() + " result: " + m6.group());
System.out.println("Matcher 7 matches " + m7.find() + " result: " + m7.group());
System.out.println("Matcher 8 matches " + m8.find() + " result: " + m8.group());

Prints:

Matcher 1 matches true result: 100,253,2586,3654
Matcher 2 matches true result: 100,253,2586,3654.999
Matcher 3 matches true result: 10,000,000,253,023,253,365,2536,2563,253
Matcher 4 matches true result: 10,000,456,258.99
Matcher 5 matches true result: 10.99
Matcher 6 matches true result: 1
Matcher 7 matches true result: 100,253,2586,3654.00000
Matcher 8 matches true result: 100,253,2586,3654.00000