如何在字符串的开头创建用于删除所有“0”的正则表达式？

Question

How delete all "0" at the beginning of string?

00011 -> 11
00123 -> 123
000101 -> 101
101 -> 101
000002500 -> 2500

I tried:

            Pattern pattern = Pattern.compile("([1-9]{1}[0-9]?+)");
            Matcher matcher = pattern.matcher("00049");
            matcher.matches();
            whatYouNeed = matcher.group();

I have error: No match found

Answer 1

I'd try

System.out.println("Status: " + "00012010003".replaceAll("^0+", ""));   

or regex only:

yourString.replaceAll("^0+", "");

Where

^ - matches only at start of string
0 - matches literal zeroes
+ - matches consecutive zeroes (at least one)

Answer 2

您应该将replaceAll与^0*并替换为empty string而不是找到匹配项。

Answer 3

If your String only contains digits as stated in your question. You can use String.valueOf(Integer.parseInt("00011"))

Answer 4

You will have to use regex (?<=^)0+ with replaceFirst() for this.
But parse your value to string before regex if it is in another form.

String val = "000011100";
String newVal = val.replaceFirst("(?<=^)0+", "");
System.out.println(newVal);

Output :

11100

Where ?<=^ is a look behind. The regex pattern will match only 0 's with ^ ie start of string behind them.